Open Photography Forums  
HOME FORUMS NEWS FAQ SEARCH

Go Back   Open Photography Forums > Digital Camera Discussion > All other DSLR's and Four Thirds, 4/3

All other DSLR's and Four Thirds, 4/3 All DSLRs excluding Canon and Nikon mounts ie Sigma, Pentax, Olympus, Sony, Leica R Back DSLRs and 4/3 System

Reply
 
Thread Tools Display Modes
  #1  
Old April 11th, 2014, 02:12 PM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default On "larger format" cameras

It's curious that there is no forum section devoted to "larger than ff35 format" cameras generally. So I write here.

************************

In a recent thread initiated by mention of a recently-announced digital camera with a "larger than ff35 format size", Theodoros reminded us that photographers only use a "larger format" camera when a "smaller format" camera is not appropriate for the job at hand.
This observation was made while deprecating one of my analyses of depth of field and diffraction implications of differing format sizes -I think "false assumptions" were mentioned.
It's a good point. It works the same way with frypans and sledge hammers.

But, moving beyond "it is well known that", what are the actual describable properties - perhaps in terms of aspects of the resulting image "quality", or perhaps in terms of the ease or practicality of attaining such - that we reach for by choosing a "larger format" camera?

And what technical mechanisms bring each of these advantages into being?

Best regards,

Doug
Reply With Quote
  #2  
Old April 11th, 2014, 02:48 PM
Asher Kelman Asher Kelman is offline
OPF Owner/Editor-in-Chief
 
Join Date: Apr 2006
Posts: 33,941
Default

Quote:
Originally Posted by Doug Kerr View Post
It's curious that there is no forum section devoted to "larger than ff35 format" cameras generally. So I write here.

************************


But, moving beyond "it is well known that", what are the actual describable properties - perhaps in terms of aspects of the resulting image "quality", or perhaps in terms of the ease or practicality of attaining such - that we reach for by choosing a "larger format" camera?

And what technical mechanisms bring each of these advantages into being?
Doug,

At the moment i'm preparing digital files to make a 8"x10" transparencies to send off for Cibachrome prints and to compare that with prints made by Canon and Epson injket and photosensitive real photography paper!

I then will decide whether or not my files are rich, robust and detailed enough for the 82" print size I need. I'll compare this with transparency film shot directly in my 8"x10" camera. It turns out that there might be some MP 200-800 MP equivalent or more detail in the film if exposed and processed and scanned properly.

The 4x5 images, (scanned at 3300 dpi), at 13,000 x 16,300 pixels, allow sharp images of 43 x 54 inches at 300 DPI (sharp when viewed from about 10 inches). But you can't see the whole image that close to it, so you must view from further away. That means the print could be even larger and it will still appear sharp. Thus, for whole image viewing, virtually any size enlargement is possible with large format photography, and the limit to detail is your eyes, not the image.[url=http://www.clarkvision.com/articles/scandetail/index.html#printpixels[/url]

My 8x10 images should print 4x larger, ie 83"x110" so 50" x 82" is no big deal at all.

Now the digital file might very well produce an perfectly marketable and impressive print of the same size, but it will depend on how important detail is in the picture.

I'm just going to try! First the best digital files I have to see how large they can be printed and not look soft. However, my plan is to move to 8x10 film if I can develop an efficient workflow.

However, most folk are happy viewing giant prints at giant distances or at least at 1 meter. So most photographers will manage just a 20-24 MP DSLR or else a 40-80 MP MF back.

My theory is that the DSLR can be used for composition and then a few shots are taken with a well calibrated 8x10 film camera.

That, at least, is my own use of LF for artistic expression in large prints, hardly something that's relevant to most folk.

Still, I'd commend taking at least some film pictures at a wedding or a board meeting, simply because one has great detail and the scanned file or projected image will be exceptionally robust.


Asher
__________________
Follow us on Twitter at @opfweb

Our purpose is getting to an impressive photograph. So we encourage browsing and then feedback. Consider a link to your galleries annotated, C&C welcomed. Images posted within OPF are assumed to be for Comment & Critique, unless otherwise designated.
Reply With Quote
  #3  
Old April 11th, 2014, 04:55 PM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default

Hi, Asher,

Thanks for the description of your interesting project. I'll be interested in your findings.

I don't quite understand how this project really relates to the matter about which I was inquiring - the impact of format size on properties of value to us.

And I''m not sure exactly what you are doing anyway.

I'll embed further questions.
Quote:
Originally Posted by Asher Kelman View Post
At the moment i'm preparing digital files...
I'd be interested in what kind of camera these were shot with - what format, among other things. Or are they scanned from images taken with film technique?

Quote:
...to make a 8"x10" transparencies...
It would be interesting to know what these transparencies will be written with.

Quote:
... to send off for Cibachrome prints...
Ilfochrome. These will be contact prints?

Quote:
...and to compare that with prints made by Canon and Epson injket and photosensitive real photography paper!
What do you mean by that last? Are you referring to the "Cibachrome" prints you discussed just previously, or is this a third workflow?

Quote:
I then will decide whether or not my files are rich, robust and detailed enough for the 82" print size I need. I'll compare this with transparency film shot directly in my 8"x10" camera.
Are we speaking here of a roughly 8" × 10" format?

Will you be comparing these positive transparencies with the prints made from the transparencies made from the digital files and the print made "directly" from the digital files?

Quote:
It turns out that there might be some MP 200-800 MP equivalent or more detail in the film if exposed and processed and scanned properly.
Oh, you plan to scan the diapositives?. Then will you make prints from the digital files to compare with the prints made from digital files made with a digital camera (per the earlier part of the story)?
If those were 8 × 10 diapositives, then 400 Mpx (the geometric mean of the range of "detail" you mention) would correspond to about 45 cy/mm on the diapositive. That seems quite reasonable.
Quote:
The 4x5 images, (scanned at 3300 dpi), at 13,000 x 16,300 pixels, allow sharp images of 43 x 54 inches at 300 DPI (sharp when viewed from about 10 inches).
Where do these 4 × 5 images come into the story? Were you shooting 4 × 5 positives in that 8 × 10 camera?

In any case, let me pick up on some matters that do relate to my inquiry. I'll repeat part of your note:

Quote:
I then will decide whether or not my files are rich, robust and detailed enough...
Of course, as an engineer, I would like to know just what "rich" and "robust" are - not necessarily as quantifiable metrics (although that would be good) but at least as describable quantitative properties.

Are richness and robustness properties that we can expect to be "better" in digital images from a "larger format" camera compared to a "smaller format" camera? And if so, what are the technical mechanisms that make that so?

Thanks.

Best regards,

Doug
Reply With Quote
  #4  
Old April 11th, 2014, 05:21 PM
Asher Kelman Asher Kelman is offline
OPF Owner/Editor-in-Chief
 
Join Date: Apr 2006
Posts: 33,941
Default

I want to produce images of people at life size or more, such that, up close, one feels the presence more than just a fabulous portrait. I've experienced this with giant Cibachrome prints made as direct positives in a life size camera.

However, the likely resolution within that is less than the technique likely produces, as we are limited by what the eye can perceive. I want to see if we can reproduce that special presence with prints derived from 8x10 film and also with a digital camera.

This is my own example of a use of LF to go beyond the detail strage capacity of the current DSLR's we have. Still, I'm testing this to see if my need for huge detail is truly essential for getting the experience I want to recreate.

The look of LF one likes, might just be more related to the way gradients in tone are expressed or the DOF of the way the camera system is set up to focus with a certain lens.

It could be that I'm actually being seduced by the "character" of of the "process" lenses that were used to make the life-size prints I admire so much.

In any case, my use of LF relates to quest for more detail. But there's more. I like the physicality of the camera with my direct access to the recording medium and the need to decide everything before the shutter is released.

So for me, it's a lot about quest for fine large images but also, a journey with a wooden camera with supple leather bellows and a lens board and film added, 2 sheets at a time in a film holder.

Asher
__________________
Follow us on Twitter at @opfweb

Our purpose is getting to an impressive photograph. So we encourage browsing and then feedback. Consider a link to your galleries annotated, C&C welcomed. Images posted within OPF are assumed to be for Comment & Critique, unless otherwise designated.
Reply With Quote
  #5  
Old April 11th, 2014, 05:41 PM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default

Hi, Asher,

That sounds like a really interesting quest. I'll be looking forward to learning of your findings.

Thanks.

Best regards,

Doug
Reply With Quote
  #6  
Old April 11th, 2014, 05:53 PM
Asher Kelman Asher Kelman is offline
OPF Owner/Editor-in-Chief
 
Join Date: Apr 2006
Posts: 33,941
Default

Doug, let me restart.

Firstly large format is a mechanism by which a large, inexpensive, simple, easily acquired surface area of image information can be fixed and stored. It is surface area dependent, with a diffraction limited lens system, essentially, within the limits of avaialble camera sizes, the more surface area, the more information recorded.

Next, the medium, if made as a transparency, has the dimensions that allow inspection directly of the image within the actual storage medium with just diffused illumination of a light box. There's no digital intermediate stage to intervene between the medium and the experience of the photographer and no computer is to interpret the signals stored in an electronic file. So it's very simple and down to earth.

There's also a different speed of working, one that requires some sense of accountability for each action one takes. By contrast, digital photography can be carried out, shooting large numbers of frames without such sense of immediate importance for resources used. Therefore, the LF method might give rise to a more disciplined approach to image making, where one must visualize more earnestly the planned capture as, each sheet of film is so important in itself.

So film work with LF carries with it the ideas of great potential for reproduction of detail and a slower more purposeful approach. Also each describable finite minute point in the film is a single shade of some actual hue of color. The colors in digital, however, are generated by mathematics based on light arriving at identical pixels but with different pixels colored either red, green or blue. Thus on a microscopic level, the storage and representation of color is different. I'm not claiming to be able to identify a print from film from a mixture of film and digital prints, but I believe that the direct writing of light to film media might contribute to the special experience direct positive film material like perhaps Polaroid or definitely Cibachrome provides us.

If one needs to make a copy of a major giant work of art in one shot, LF film would be the most direct approach. This is why some galleries have demanded LF photographs of their precious paintings.

Asher
__________________
Follow us on Twitter at @opfweb

Our purpose is getting to an impressive photograph. So we encourage browsing and then feedback. Consider a link to your galleries annotated, C&C welcomed. Images posted within OPF are assumed to be for Comment & Critique, unless otherwise designated.
Reply With Quote
  #7  
Old April 11th, 2014, 06:37 PM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default

Hi, Asher,

Thanks for that review of the whole situation.

One key relationship is that if for any consistent f-number, our "resolution" is in every case essentially diffraction limited
[that is, in every case the lens aberrations would suggest a resolution better than that dictated by diffraction at that f-number]
then for that consistent f-number, the amount of "information" captured (in the resolution sense) goes essentially as the area of the image at the focal plane.

Very interesting.

Thanks again.

Best regards,

Doug
Reply With Quote
  #8  
Old April 11th, 2014, 06:46 PM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default

Hi, Asher,

Quote:
Originally Posted by Asher Kelman View Post

If one needs to make a copy of a major giant work of art in one shot, LF film would be the most direct approach. This is why some galleries have demanded LF photographs of their precious paintings.
I don't understand "in one shot". If we shot the artwork with an "MF" film camera, or a full-frame 35-mm film camera , or a digital camera with a 75 mm × 100 mm sensor, how would that not make doing it "in one shot" practical?

What am I missing here?

Best regards,

Doug
Reply With Quote
  #9  
Old April 11th, 2014, 08:42 PM
Asher Kelman Asher Kelman is offline
OPF Owner/Editor-in-Chief
 
Join Date: Apr 2006
Posts: 33,941
Default

Quote:
Originally Posted by Doug Kerr View Post
Hi, Asher,



I don't understand "in one shot". If we shot the artwork with an "MF" film camera, or a full-frame 35-mm film camera , or a digital camera with a 75 mm × 100 mm sensor, how would that not make doing it "in one shot" practical?

What am I missing here?

Best regards,

Doug
Detail, that's what's missing! The digital back can go up to 80MP but the artwork, say 8ft x 10ft has a potential set of details of something like 1000 dpi. That cannot be captured by any digital back. However, film can hold much more. The best can hold 4,000 to 8,000 lines of detail per inch. So, only LF film could capture such detail as is findable in the original painting.

Still, the picture taken with either an 80MP Phase One or a 24MP Canon DSLR or a 16MP Olympus OM-D E M1 would all be very impressive despite the lack of the finest discoverable detail on the microscopic, sub-brush stroke level.

Asher
__________________
Follow us on Twitter at @opfweb

Our purpose is getting to an impressive photograph. So we encourage browsing and then feedback. Consider a link to your galleries annotated, C&C welcomed. Images posted within OPF are assumed to be for Comment & Critique, unless otherwise designated.
Reply With Quote
  #10  
Old April 11th, 2014, 10:57 PM
Jerome Marot Jerome Marot is offline
Senior Member
 
Join Date: Jan 2011
Location: Munich, Germany.
Posts: 3,645
Default

Quote:
Originally Posted by Doug Kerr View Post
In a recent thread initiated by mention of a recently-announced digital camera with a "larger than ff35 format size", Theodoros reminded us that photographers only use a "larger format" camera when a "smaller format" camera is not appropriate for the job at hand.
This observation was made while deprecating one of my analyses of depth of field and diffraction implications of differing format sizes -I think "false assumptions" were mentioned.

Not "false". I wrote: "the discussion of depth of field resides on assumptions that do not correspond to actual photographic practice. The formulas underlying hypothesis is that, whatever the camera, one will produce prints of the same size (or observe larger prints from a greater distance). This is not what people do and for a good reason: it does not make sense to buy and carry around a bigger and more expensive camera to produce the same pictures as with a smaller and cheaper camera."

This thread, message #17.


Quote:
But, moving beyond "it is well known that", what are the actual describable properties - perhaps in terms of aspects of the resulting image "quality", or perhaps in terms of the ease or practicality of attaining such - that we reach for by choosing a "larger format" camera?
One was implicit from the text cited above: produce larger prints, to be observed from a close distance and still look sharp.
Reply With Quote
  #11  
Old April 11th, 2014, 11:06 PM
Jerome Marot Jerome Marot is offline
Senior Member
 
Join Date: Jan 2011
Location: Munich, Germany.
Posts: 3,645
Default

Quote:
Originally Posted by Asher Kelman View Post
If one needs to make a copy of a major giant work of art in one shot, LF film would be the most direct approach. This is why some galleries have demanded LF photographs of their precious paintings.
This: http://www.endetail.fr is done by a team of two French photographers with a MF camera, 2 flashes and a set of rails to move the camera around the painting. There is a making off video on their facebook page.

This: http://www.haltadefinizione.com/en/ is the same done with a higher budget.
Reply With Quote
  #12  
Old April 11th, 2014, 11:32 PM
Asher Kelman Asher Kelman is offline
OPF Owner/Editor-in-Chief
 
Join Date: Apr 2006
Posts: 33,941
Default

Quote:
Originally Posted by Jerome Marot View Post
This: http://www.endetail.fr is done by a team of two French photographers with a MF camera, 2 flashes and a set of rails to move the camera around the painting. There is a making off video on their facebook page.

This: http://www.haltadefinizione.com/en/ is the same done with a higher budget.
In the future, tiny robots will fly above the painting and collect and align all the pixels automatically giving not only all the possible detail but also the 3D date of each paint stroke and the canvase it sits on!

Asher
__________________
Follow us on Twitter at @opfweb

Our purpose is getting to an impressive photograph. So we encourage browsing and then feedback. Consider a link to your galleries annotated, C&C welcomed. Images posted within OPF are assumed to be for Comment & Critique, unless otherwise designated.
Reply With Quote
  #13  
Old April 12th, 2014, 02:28 AM
Jerome Marot Jerome Marot is offline
Senior Member
 
Join Date: Jan 2011
Location: Munich, Germany.
Posts: 3,645
Default

Quote:
Originally Posted by Doug Kerr View Post
Of course, as an engineer, I would like to know just what "rich" and "robust" are - not necessarily as quantifiable metrics (although that would be good) but at least as describable quantitative properties.

Are richness and robustness properties that we can expect to be "better" in digital images from a "larger format" camera compared to a "smaller format" camera? And if so, what are the technical mechanisms that make that so?
Now, these are very good questions. I did not notice them at first. Maybe I can give the beginning of an explanation.

When a photographer speaks about "richness", he or she usually means that there is lots of details in the image. Either spatial details or colour details. Basically, it refers to the experience of discovering in the image details that were present in the original subject but too small or subdued to be obvious at normal observation distance.

When a photographer speaks about "robustness", he or she usually means that "richness" (as defined above) will survive manipulations (usually digital manipulations nowadays). It belongs to common photography practice that images are manipulated before being printed: the contrast and colour balance may be adjusted for example. When one adjusts a picture (e.g. with digital sliders, but also in an analog lab), one will quickly notice that there is a range of adjustments within which the image will still be believable but when one goes outside that range problems become obvious. For example: artefacts may appear. The wider the range, the more "robust" a picture is.

A good example of "less rich" pictures are compressed jpeg pictures. Jpeg is dependent on the limitations of human vision to achieve good compression. For example, it spends less data on dark parts, because human vision is less sensitive to details in the darker parts. When one raises the shadows, this becomes obvious and the image breaks (which is to be expected).

Now to the question whether a larger sensor will improve these characteristics: as a rule of thumb, yes. But the reasons are multiple (and different for digital and analog cameras) and I am not sure this is the best approach to talk about the difference arising from sensor size. In any case, I have already posted an essay about the differences a few months ago.
Reply With Quote
  #14  
Old April 12th, 2014, 06:22 AM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default

Hi, Jerome,

Quote:
Originally Posted by Jerome Marot View Post
Not "false". I wrote: "the discussion of depth of field resides on assumptions that do not correspond to actual photographic practice. The formulas underlying hypothesis is that, whatever the camera, one will produce prints of the same size (or observe larger prints from a greater distance). This is not what people do and for a good reason: it does not make sense to buy and carry around a bigger and more expensive camera to produce the same pictures as with a smaller and cheaper camera."

This thread, message #17.
As I said in my original post in this thread, I was not referring to your comment.

But my memory of the dialog may be faulty!

Best regards,

Doug
Reply With Quote
  #15  
Old April 12th, 2014, 06:24 AM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default

Hi, Asher,

Oh, I get it. By "in one shot", you mean, "as distinguished from taking multiple shots of parts of the subject and stitching them together."

Sorry I missed that.

Best regards,

Doug
Reply With Quote
  #16  
Old April 12th, 2014, 06:42 AM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default

Mea culpa.

In my opening post of this thread, I incorrectly attributed to Theodoros some observations that were actually made by Jerome.

And in fact Jerome did not describe the assumptions I had adopted in a certain comparison as "false", as I had said in my opening post. As he recently reminded us, he said that they do not correspond to actual photographic practice.

My sincere apologies to both my colleagues.

Best regards,

Doug
Reply With Quote
  #17  
Old April 12th, 2014, 06:45 AM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default

Hi, Jerome,

Quote:
Originally Posted by Jerome Marot View Post
Now, these are very good questions. I did not notice them at first. Maybe I can give the beginning of an explanation.

When a photographer speaks about "richness", he or she usually means that there is lots of details in the image. Either spatial details or colour details. Basically, it refers to the experience of discovering in the image details that were present in the original subject but too small or subdued to be obvious at normal observation distance.

When a photographer speaks about "robustness", he or she usually means that "richness" (as defined above) will survive manipulations (usually digital manipulations nowadays). It belongs to common photography practice that images are manipulated before being printed: the contrast and colour balance may be adjusted for example. When one adjusts a picture (e.g. with digital sliders, but also in an analog lab), one will quickly notice that there is a range of adjustments within which the image will still be believable but when one goes outside that range problems become obvious. For example: artefacts may appear. The wider the range, the more "robust" a picture is.
Thank you for those insights.

Quote:
A good example of "less rich" pictures are compressed jpeg pictures. Jpeg is dependent on the limitations of human vision to achieve good compression. For example, it spends less data on dark parts, because human vision is less sensitive to details in the darker parts. When one raises the shadows, this becomes obvious and the image breaks (which is to be expected).

Now to the question whether a larger sensor will improve these characteristics: as a rule of thumb, yes. But the reasons are multiple (and different for digital and analog cameras) and I am not sure this is the best approach to talk about the difference arising from sensor size. In any case, I have already posted an essay about the differences a few months ago.
Could you help me find that essay.

Thanks.

Best regards,

Doug
Reply With Quote
  #18  
Old April 12th, 2014, 07:01 AM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default

Hi, Asher,

What I seem to take away from your very interesting discussions is this:

What the use of a larger-format camera gives us is, simplistically, "more and more robust detail" (and Jerome reminds us that there are at least two aspects to this concept - spatial detail and color "detail").

The larger format camera gives us this because it uses film, not a digital sensor.

I was not expecting an answer of that nature, but it is interesting.

Or do I miss the point? Perhaps it is more obvious:

• A larger format gives us more and more robust detail.

• It is more economically practical at this time to implement a larger format with film than with a digital sensor.

I guess a practical application of that, given that in many cases, a digital intermediate result is needed, is:

It is more economically practical at this time to generate a high-quality large pixel count digital image by shooting with film in a large format and scanning it with a high-quality film scanner than to generate it directly with a large-format digital sensor.

All very interesting.

Best regards,

Doug
Reply With Quote
  #19  
Old April 12th, 2014, 08:25 AM
Asher Kelman Asher Kelman is offline
OPF Owner/Editor-in-Chief
 
Join Date: Apr 2006
Posts: 33,941
Default

Quote:
Originally Posted by Doug Kerr View Post
Hi, Asher,

What I seem to take away from your very interesting discussions is this:

What the use of a larger-format camera gives us is, simplistically, "more and more robust detail" (and Jerome reminds us that there are at least two aspects to this concept - spatial detail and color "detail").

The larger format camera gives us this because it uses film, not a digital sensor.

I was not expecting an answer of that nature, but it is interesting.

Or do I miss the point? Perhaps it is more obvious:

• A larger format gives us more and more robust detail.

• It is more economically practical at this time to implement a larger format with film than with a digital sensor.

I guess a practical application of that, given that in many cases, a digital intermediate result is needed, is:

It is more economically practical at this time to generate a high-quality large pixel count digital image by shooting with film in a large format and scanning it with a high-quality film scanner than to generate it directly with a large-format digital sensor.

All very interesting.

Best regards,

Doug
All correct. But there's more. Folk use the film camera and with favorite lenses to deliver images of certain "character" related to many effects an individual lens might impose on a theoretically perfectly-focused and evenly-illuminated image. The image is considered to be "written" in a "personal" way by certain favored lenses and help contribute to the esthetic experience of enjoying the resulting image.

Look a at Jerome's article, but one also gets swings, tilts and shifts of the lens and/or the field plane to keep geometry orthogonal and the put a plane of sharp focus almost anywhere in front of the camera.

Lastly, LF, like fishing, butterfly collecting and bird photography, can be a wonderfuly immersive hobby!

Asher
__________________
Follow us on Twitter at @opfweb

Our purpose is getting to an impressive photograph. So we encourage browsing and then feedback. Consider a link to your galleries annotated, C&C welcomed. Images posted within OPF are assumed to be for Comment & Critique, unless otherwise designated.
Reply With Quote
  #20  
Old April 12th, 2014, 11:34 AM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default

Hi, Asher,

In your initial response to my inquiry, you discussed one "project" which I take to be this: you will compare "life-size" Ilfochrome (Cibachrome) prints of images of persons produced:

A. (I assume by optical enlargement) from 8×10 diapositives (positive transparencies) shot in an 8×10 view camera.

B. (I assume by optical enlargement) from 8×10 diapositives generated from digital files.

Is that a correct understanding of the project?

Regarding case B, I would be inserted to know of the source of these digital images. Will they have been shot in a digital camera, and if so, with about what format size and pixel count? Or what.

How will they be written to the 8×10 diapositives?

Thanks.

Best regards,

Doug
Reply With Quote
  #21  
Old April 12th, 2014, 12:42 PM
Asher Kelman Asher Kelman is offline
OPF Owner/Editor-in-Chief
 
Join Date: Apr 2006
Posts: 33,941
Default

Quote:
Originally Posted by Doug Kerr View Post
Hi, Asher,

In your initial response to my inquiry, you discussed one "project" which I take to be this: you will compare "life-size" Ilfochrome (Cibachrome) prints of images of persons produced:

A. (I assume by optical enlargement) from 8×10 diapositives (positive transparencies) shot in an 8×10 view camera.
Exactly.

B. (I assume by optical enlargement) from 8×10 diapositives generated from digital files.

Is that a correct understanding of the project?[/quote]

Also correct.

Quote:
Originally Posted by Doug Kerr View Post
Regarding case B, I would be interested to know of the source of these digital images. Will they have been shot in a digital camera, and if so, with about what format size and pixel count? Or what.
Here I'll use some of the best digital files of pictures, (using the Canon 5DII or Canon 6D), I already have, (the kind I'd like to print big anyway). The data will be printed with a LightJet on to Velvia film and then given to the Cibachrome lab to print. It will be at both 8x10 and also a strip at 100 % using 300 dpi.

The same file will be printed to the same size by a print house that prints work for photographic artist, "as "fine Art". The use Canon inject printers with 12 pigment inks.

This part of the tests is to explore the nature of Cibachrome with the Canon digital print to see if they give any experience close to what the direct Cibachrome prints have evoked for me.

Asher
__________________
Follow us on Twitter at @opfweb

Our purpose is getting to an impressive photograph. So we encourage browsing and then feedback. Consider a link to your galleries annotated, C&C welcomed. Images posted within OPF are assumed to be for Comment & Critique, unless otherwise designated.
Reply With Quote
  #22  
Old April 12th, 2014, 02:09 PM
Doug Kerr Doug Kerr is offline
Senior Member
 
Join Date: May 2006
Location: Alamogordo, New Mexico, USA
Posts: 8,398
Default

Hi, Asher,

Thanks for the very clear response.
Quote:
Originally Posted by Asher Kelman View Post
Exactly.

Quote:
B. (I assume by optical enlargement) from 8×10 diapositives generated from digital files.

Is that a correct understanding of the project?
Also correct.

Here I'll use some of the best digital files of pictures, (using the Canon 5DII or Canon 6D), I already have, (the kind I'd like to print big anyway). The data will be printed with a LightJet on to Velvia film and then given to the Cibachrome lab to print. It will be at both 8x10 and also a strip at 100 % using 300 dpi.
So in each case the original capture (in camera) is on a 36 mm × 24 mm format with a pixel count in the neighborhood of 20 Mpx.

I note that the renderings on the strip are "downsampled" about 13:1.

It is interesting to compare the resolution potential of the digital file and the 8×10 Velvia interpositive. The resolution potential of the digital file is about 1390 cycles per picture height (24 mm). The resolution potential of the 8×10 Velvia interpositive medium itself is probably about 16,000 cycles per picture height (about 80 cy/mm).

But I think the resolution potential of the LightJet (for an 8×10 output) is about 900 cy/picture height (8 in). (That is not a highly authentic value!)

So the passage though the LightJet probably slightly degrades the resultion potential of the originally-digital files.

And of course I don't know what resolution we might expect of the 8×10 view camera (with whatever lens) shooting onto Velvia.

Quote:
The same file will be printed to the same size by a print house that prints work for photographic artist, "as "fine Art". The use Canon inject printers with 12 pigment inks.
What print size will you typically have made?

Quote:
This part of the tests is to explore the nature of Cibachrome with the Canon digital print to see if they give any experience close to what the direct Cibachrome prints have evoked for me.
As I said, I will be very interested to hear of your findings.

Thanks.

Best regards,

Doug
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are Off
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Sensor sizes for compact cameras Doug Kerr Digital Rangefinder & Digicams and yes, even Cell Phones! 0 August 25th, 2011 10:01 AM
Cameras compensating for an undesirable phenomenon Doug Kerr Imaging Technology: Theory, Alternatives, Practice and Advances. 22 November 7th, 2010 08:00 PM
News: Soon, the 500 Kg Gorilla from Japan: Smaller Canons : New DSLR-like small cameras! Asher Kelman Breaking News 4 July 29th, 2010 07:29 PM
News: DXO Expands coverage to MF Digital Cameras! Asher Kelman Breaking News 4 February 4th, 2009 01:36 PM
5 cameras to one Mac? René Damkot Image Processing and Workflow 5 December 6th, 2007 02:06 AM


All times are GMT -7. The time now is 01:52 PM.


Posting images or text grants license to OPF, yet © of such remain with its creator. Still, all assembled discussion © 2006-2017 Asher Kelman (all rights reserved) Posts with new theme or unusual image might be moved/copied to a new thread!