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Digital Large Format

JimCollum

pro member
Asher Kelman said:
Jim,

How do these 100% crops sharpen?

Asher
a mixed bag. the Cooke captures things both sharp and unsharp.. so you end up with a sharp image of the subject inside a diffuse/glow of the subject. i'm normally pretty happy with the sharpness coming out of the Betterlight (no anti alias, no interpolation, no bayer, etc), and prefer things to maintain a 'natural' sharpness than to increase it.

that said.. if you click on the 100% crops, you'll get a window with a larger (the actual) 100% crop of the image. feel free to take any of those and play with them

some more at

http://web1.omniblog.com/_smartsite/modules/local/blog/blog_display.php?cmd=show_blog&user_id=10004&type=entry&map_id=1195



jim
 

Jack_Flesher

New member
Here is a quick detail sample from one of my dilapidated building shots from last week. The whole image was shot in 6K capture mode (6000x8000 pixels). Most interesting is this was a dark room so I had to use ISO 2000 and about a 3 minute scan time. The Betterlight Super 6K plus goes to ISO 3200 yet it has exceptional noise traits as you can see in this shot. Thre was NO noise reduction run on this image or the crop.

Here is the full frame. Note the DR looking into the very dark room behind the door. In a print you can see into this area very well:


And here is a crop of the faucet and sink. This is a 600x800 pixel crop at actual pixels, so it represents exactly 1/100th of the total image. You can see the noise under the sink against the green wall. I have printed this out at 24x32 inches and you cannot see that noise in the print. I have uprezzed it and printed this portion of it at an effective 48x64 inches and you can just see the noise if your nose is in the print. The detail remains phenomenal even at that print size:


Cheers,
 
Ok, here is the problem

I am very thank full of Mike Collete from BetterLight that has accepted me in the owners forum. I don't have a scanning back, but have to find a digital capture to photograph art work for galleries.

He answer one of my most important questions regarding the (informal) feasibility study of a scanning back.

The problem that I have is that I wish to work more on location than in studio for various reasons, so the capture system has to fit well in a taxi cabs trunk.

I don't know if carbon copy Mike Collete's response here is good or bad, but probably anyone that has ever used a scanning back knows what he said and is no proprietary secret... so here it is..


A - Tungsten hot lights will work OK, but location shoots often have
problems with not having enough different circuits to power the
required
number of tungsten lights, and/or problems with AC mains voltage
variations
that can cause tungsten lights to vary in intensity during a scan,
producing
faint dark/light banding whenever the lights change brightness.
Lowel's
Tota lights sure are compact, but these little lights aren't very
efficient,
and you'll need to use four to six of these to produce enough light to
scan
a 30 x 40 inch subject (for example). Lowel's somewhat larger "DP"
tungsten
lights are much more efficient than the Tota lights, although you'd
still
probably want to use four of these (750-watt) fixtures to cover a 30 x
40
inch area.

There are much more efficient alternatives to tungsten lights that also
tend
to produce better color rendition, although these alternative lights
aren't
usually as small as tungsten fixtures. Some relatively compact
fluorescent
fixtures are now available, as well as some of the newer HID (High
Intensity
Discharge) fixtures. "

Since 30 x 40 inch is a small area, I would have to bring MORE than the 4,500 Watts (750w x 6 in case of Totas) and expect the gallery to be able to handle that much juice etc etc.

So what I'm thinking now is that shouldn't it be better to go in the one - shot back direction?

I could wait a few months, establish my practice using film and get a 22mb back for my Mamiya 645 AFD, -- may be a P25 or even a ZD from Mamiya, if the company resuscitates, that is...


... (the expressos made me do it...)
 

Ray West

New member
Leonardo,

I suspect in a few months time, it will all be LED. I've seen low voltage, low current prototype lights (at a customer into underwater video housing manufacturing) that is smaller and brighter, lower power than anything else they can use. And, they don't get too hot (although these need a heatsink and cooling fan for video use)

I do not think this is available yet on a wide scale commercial basis.

Best wishes,

Ray
 

Asher Kelman

OPF Owner/Editor-in-Chief
Leonardo,

What are the limits in the exposure you are not being able to meet? Jack's pictures do show a little noise, but are pretty good uncorrected, even on close inspection. Do you need much better than that?

Why do you need powerful lights?

Asher
 
Asher, I don't have the back, I just want to make a detail image in my mind of the way that a photo scanner works and what are the limitations. I know that they produce a really good image and is probably unbeatable in a studio set up, but I will have no studio and location conditions may vary from good to no so good etc.

Can you tell me your experience with hot lights please? the more info I have the best decision I can take.

Thanks

Asher Kelman said:
Leonardo,

What are the limits in the exposure you are not being able to meet? Jack's pictures do show a little noise, but are pretty good uncorrected, even on close inspection. Do you need much better than that?

Why do you need powerful lights?

Asher
 

Asher Kelman

OPF Owner/Editor-in-Chief
Sorry, Leonardo, I use strobes!

However, from Jack's work and Jim's work, I don't see any special need for bright lights.

Asher
 
The diference is that I would have to make precise color corrected scans of paintings that may be 6 feets x 7 feets, with even light from corner to corner and in the center.

I would be realy happy to be able to do this with 4 500watts Totas, but from the explanation that I got from Mike Colette this may be difficult to achieve, at least on location.

thanks, leonardo
 
leonardobarreto.com said:
The diference is that I would have to make precise color corrected scans of paintings that may be 6 feets x 7 feets, with even light from corner to corner and in the center.

I would be realy happy to be able to do this with 4 500watts Totas, but from the explanation that I got from Mike Colette this may be difficult to achieve, at least on location.

thanks, leonardo
i was interested to scanbacks before i went the mf route,- i thought it might work for architecture, at leastfor interior. but after some research i really thought that it will not make my life easier... and about the price,- if i buy an actual betterlight which reads fast, and all the additional costs i will need, i am not so sure that this will come out as a "cheap" solution. and.... the new 33mp eMotion delivers now detail as 4x5" or more in a quality i havent seen before. just was shooting churches where i had to reproduce the paintings at the ceiling. its so incredible good how it came out.... and it is manageable. even with 4x5".
this was always a painfull ( for my back ) thing to shoot this ceiling - images with 4x5"..... and the results were not comparable than with my new mf back.

see this 100% image of the ceiling i am speaking.

http://www.tangential.de/e75-testshots/images_fullres/bi-internet.jpg
 

Asher Kelman

OPF Owner/Editor-in-Chief
Rainer,

Wonderful! I am amazed by this picture. What was the lens used?

I'm scared to ask the price! Still, explain to those less fortunate, why Betterlight couldn't do this? IOW, what would be deficient in a scan image inside the Church. On first glance, it would seem that a scanning back should work fine in this interior shot.

For 6'x7' art your Sinar would be perfect!

Asher
 
Asher Kelman said:
Rainer,

Wonderful! I am amazed by this picture. What was the lens used?

I'm scared to ask the price! Still, explain to those less fortunate, why Betterlight couldn't do this? IOW, what would be deficient in a scan image inside the Church. On first glance, it would seem that a scanning back should work fine in this interior shot.

For 6'x7' art your Sinar would be perfect!

Asher
hi asher,
thank you for your nice comments....

well the scanback simply will not match the exposure time of 20seconds / iso50 in the second shot.
the first shot ( the image repro ), everybody who has shot this kind of things know how hard it is to justage the camera for shots over you, if you want to bring them really in parallel. its very hard with 4x5" and much harder with a scanback..... and: you will often have the problem that even in a situation like this in the long minutes you will need to expose the image a cloud will pass or the light will change slightly, and than you will come out with stripes in your image. sometimes it may work, sometimes not.
and make a kalkulation which times you can reach with the best scanbacks,- i think more than an equ. of 1 or 2 seconds / iso100 you will not reach and even for this you will need a lot of time for the scanning.


the lense which was used in both shots is the fabulous sinaron 28HR together with the e75 also from sinar.
 

JimCollum

pro member
although the Betterlight has better noise characteristics than single capture, they don't do well in low light situations.. max is about iso 3200 @ 1/8 sec exposure on a single capture device.. and at that speed, it gets pretty noisy. low light interiors is not where i'd be using a scan back (which is why i carry a few sheets of film with me as well :^)

jim
 

Jack_Flesher

New member
Just to help put things in perspective, the washroom scan I shared above was taken at a scan time of about 3.4 minutes at ISO 2000, which is equal to around a 1 second exposure at ISO 100 with a single-capture device.

But I should also point out there was 9+ stops of exposure difference between the lightest part of the green wall below the light-switch and the dark window in the door...

Cheers,
 
I'm leaning towards the one shot back for my Mamiya 645 AFD system for many reasons

-- There are new 30mp backs coming in to the market so this will bring the price of new and used 22mp backs down, there are all ready some P25 (with the H1 included) at about $13k.

-- 22mp and Mamiya optics is good enough convination.

-- Mamiya may be back in business with the value added of a software new mother firm.

-- Much more versatile system,

-- Compared to scanning back, a $10k PhaseOne P25 is better in terms of cost.

So that's it I will just wait.

I only have one question left: can this backs (one shot) be used with tungsten? I know that my Fujifilm S2 can be set to the reading in my Minolta color meter and produce a balanced image. I would be perfect to use the same lights I use for transparencies.

Leonardo

ps Rainver, I don't think that church interior is "nearly incredible", it is incredible.
 
DL, Is there a limit on the exposure time? there is no reciprocity failure like in film, is it?

A veteran 8x10 transparency photographer said to me that colors where capture best in film with longer times than (may be flash?) don't know if it is true with film, but what about with a digital back?

Many photographers doing reproduction plates of art work use tungsten, so I could just bring the 645AFD+back along with the Sinar in case they want film and digital and use the same set up of hot lights.

I wonder if I could offer the to shoot digital and "make" transparencies out of the files, this way they could use the digital file for catalog printing, to make slides or transparencies...

Thank you again to every one in this thread that is helping me make my business plan :)
 

Jack_Flesher

New member
You keep mentioning reproduction of art, so I will add a few more coments...

You can WB for tungsten with any digital back, but the color of the light itself can severely limit your ability to reproduce all of the colors in the original art piece accurately. At the very least, you will have to have an excellent profile for your camera under tungsten and getting one is not an easy task. It is why HID and CCT lights are popular choices for art repro under continuous lighting. For a single capture back, a good strobe would be a much better choice -- but only IF the art director at the museum will allow you to use them.
 
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Don Lashier

New member
Jack_Flesher said:
You can WB for tungsten with any digital back, but the color of the light itself can severely limit your ability to reproduce all of the colors in the original art piece accurately.
Jack, I assumed Leonardo was referring to studio lights which are commonly referred to as "tungsten" (probably because they're balanced to 3200k) but are in reality Halogen. Mine are Quartz, 3200k, and a CRI of around 90. Does your precaution apply to these also or just "ordinary" tungsten? I've never had a problem with color, but admittedly have not done a lot of reproduction work.

Leonardo, no, no reciprocity failure with digital.

- DL
 

Jack_Flesher

New member
Hi Don:

When I hear tungsten, I usually do think of household bulbs in a hardware store reflector and not something like the Tota Lights ;) Anyway for critical copy work, the difference may not be enough. I am no expert in color-management, so if anybody out there is, please correct me. Here is how I understand it. Household Tungsten bulbs usually fall in at around 2800 - 2900K. A halogen/tungsten is closer to 3200K, which means more blue, but even that is still not much blue light. As a result, any object you photograph that contains significant amounts of blue won't always reproduce in print accurately since there isn't enough blue in the light for bright or saturated blues in the object to corectly reflect back to the camera. However, less saturated blues generally will do okay and this is probably why the CRI numbers look good. And it might be fine for viewing on the narrower gamut of a monitor, but may not be adequate for a printed reproduction.

This also probably isn't a problem when you are shooting subjects that don't contain much blue to begin with -- like people for example -- but I know it can be if you are trying to replicate an artwork with lots of bright and/or saturated blues and subtle transitions into the cyans and greens -- and then want to print that out as a duplicate. This is why I said a really accurate camera profile will be necesary -- and they are tough enough to build under ideal conditions, let alone under skewed light.

Cheers,
 
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Don Lashier

New member
Jack, I'm referring to professional studio lights like Photoflex and Arri (and Lowel Totas) that are commonly refered to as "tungsten" because they are balanced for tungsten film. I doubt that these would be used in studios, and for copy work, all over the world if they had serious spectrum holes.

- DL
 

Don Lashier

New member
Hi Jack,

I did find a reference to the issue you're talking about (from Betterlight, of all places), with cobalt blue as an example. But I doubt this is an issue in most cases - tungsten (quartz) halogen lights are widely used for art copy work, googling shows that the majority of references recommend them as the lighting of choice, some preferring strobes. I prefer continuous lights because it's easier to see what's going on with reflections eliminating some trial and error.

- DL
 

Jack_Flesher

New member
Don:

I never said halogen had spectrum holes -- that is a different and more significant problem! I realize halogen is continuous spectrum. All I am saying is it is significantly skewed to red and this makes it difficult to profile a digital camera under them accurately.

Have you by any chance profiled your digital camera under yours? If so, how well did that turn out -- what was your delta-e? I'd be really curious to have you copy a deep blue and share the result with us.

Cheers,
 
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Asher Kelman

OPF Owner/Editor-in-Chief
One can talk about color profiles until the cows come home.

For perfection, only using the same paint, pigment or inks will the picture look identical in all viewing conditions and at different times of the day.

Of course, there is no end to correction tables one could have for a file, but there is neither a monitor to show the image nor a printer to get a hard copy!

Just rent the best equipment you can and see how it goes with test images? The curator will tell you if it meets their standards.

Then it is much easier to respond to the following statement:

"The museum viewed my images on a calibrated Eizo XYZ monitor. They intend to print using a PQRS printer. Here are pictures taken with Phase One and Aptus backs and one scanning back using the following lights, xxxx and yyyy. The scanned image is great but lacks qqqq. I've tried these remedies, nnnn and mmmm, but they fall short."

Asher
 

Don Lashier

New member
Asher Kelman said:
Of course, there is no end to correction tables one could have for a file, but there is neither a monitor to show the image nor a printer to get a hard copy!
Very true, and I think the bigger point here is that both myself and a local artist that I've done copy work for, and who also does some of his own, have noted that it's much easier to get accurate color repro with digital than with film.

For those interested in the esoterics of repro lighting, google also turned up a research paper by RIT. This was a study of whether whether museum quality repro work can be done without visual (PS) editing, and the conclusion was yes (using tungsten-halogen btw). But note that cobalt blue had delta-e of 7.3 and phthalocyanine green was even higher at 8.6.

But the point here is that tungsten-halogen is considered the norm for quality repro lighting, cobalt blue problems or not. The objection I've heard about HMI is the high amounts of uv.

- DL
 
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Grate. It is nice to come back home to so much knowledge and argument on my thread. Thanks.

Conclusions:

-- No reciprocity failure in digital world (I sort of expected it, but good any way)
-- No good to use house hold light bulbs for high end art work copy.
-- Color control is much easier with digital than film (but with continuos or flash light ??)
-- Continuous light (quartz or halogen) do not have "serious spectrum holes" (don't know exactly what this are, but seams to be better not to have them)
-- But they are deficient in blue light so there may be problems with deep blues and transition to green and/or blue-greens. (I had a problem with my first digital assignment and this exact colors but I was using flash..)
-- Quartz and halogen lights like Lowel Totas and DP are "used in studios, and for copy work, all over the world", so they work more or less ok.

Remaining question could be

* Ideal flat fine art (color) reproduction light would be flash or continuous?
(probably the answer would be the second, but with other than halogen/quartz but some "day light" source may be.

By the way, has anyone encounter problems with the color blue when is just before it becomes green? I remembered when I was asked by an ad agency to photograph a new model of disposable shaving razors, don't remember the brand. The color was that, and came out totally wrong in digital capture (with flash), when I shot a transparency, using the same light, film reproduced the color well.

thanks, leonardo
 
I am suprised no one has mentioned gels, gel the lights and you can use either contious or flash, if using continous it may be hot make sure they dont get to close to very old painting for long periods of time. I would say gel your lights ideally with a color meter and then set the back accordingly.

Stephen
 
Stephen Eastwood said:
I am suprised no one has mentioned gels, gel the lights and you can use either contious or flash, if using continous it may be hot make sure they dont get to close to very old painting for long periods of time. I would say gel your lights ideally with a color meter and then set the back accordingly.

Stephen
It is an interesting idea. With film, tungsten balanced transparency film was used, quartz lights where balanced to the K. degrees, but small differences where always there, so small corrections had to be done measuring the light with a color meter and adding a gelatin filter in the back of the 4 x 5 lens.

With digital I think that it would be inefficient to set the camera to "day light" and then convert the "tungsten" lamps also to day light because you would loose about 50% of the "intensity".

The question would be, now that we know that this lights have a deficiency of blue, would you get it back with gelatin filters either on the lens or in front of the lights? I would guess not..
 

Jack_Flesher

New member
Don Lashier said:
But note that cobalt blue had delta-e of 7.3 and phthalocyanine green was even higher at 8.6.

But the point here is that tungsten-halogen is considered the norm for quality repro lighting, cobalt blue problems or not. The objection I've heard about HMI is the high amounts of uv.

- DL
Don:

I am not saying it can't be done -- again all I am saying is that using tungsten is going to make it tough to get accurate reproductions of saturated blues and cyans. I could not find of the date of the study you linked to and a lot has changed in the last two years. The fact is a delta-e of 7 or 8 is significant by anybody's standard. It is obviously acceptable to some museums and not others -- and even becomes irrelevant if the artwork being copied only contains red :)

FTR, I indicated HID and NOT HMI lighting -- big difference in color output.

Gelling the tungsten is a good idea, but an 80B will knock a 1000 watt light down to 500 watts in a hurry ;)

Cheers,
 

Don Lashier

New member
> I could not find of the date of the study you linked to and a lot has changed in the last two years.

February, 2005.

HID lights do look like the superior option, better spectrum, less heat, low UV - but OUCH on the price.

ps: this also begs the question (pardon improper usage), what are you trying to reproduce? The appearance of a painting in the gallery where preferred lighting is typically ~3500K halogen or the original daylight lighting only seen in the artist's studio?

- DL
 
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