Calculate this

[Asher Kelman]

It's not even that. It's how the transistion from in focus to out of focus is drawn. A 400mm lens and a 50mm lens, even with identical numerical DOF will have a very different look to the focus fall off. The shorter lens at a wide aperture will show very little in focus with an immediate fall off, a longer lens stopped down more will have the same DOF but the focus fall off is far more abrubt, cut off than the shorter lens.

Ben,

I too have been wondering about this transition so I'm very interested in your questions and experience. It's not really that obvious a sudden change in large pictures as one would imagine. In fact, one can have a full length life size portrait at f22 with the 750mm Apo Germinar, without folk realizing that the DOF is so limited.

I wonder whether using a sheet of fine nylon mesh with a hole in the center would work at f22 to make it appear more like the softness of the shorter focal lengths, such as the PS945 at f4.5 in 8x10 format. Obviously, the hole in the nylon mesh would have to be somewhere less than the diameter of the aperture. So for my 750 mm lens, for example at f22, the diameter would be less than 34.09 mm to effect the transition and "improve" the bokeh. Perhaps something like 20 mm. I wonder whether or not the circumference of the hole should be sharp or frayed. I'd imagine the latter. I'll try both.

Asher

 

[Ben Rubinstein]

Asher I couldn't tell you to be honest, sorry!

I'm now working on the stitched image, it's 3.3gb so everything is going veeeeeeeeeeeeeery sloooooooooooowly! The difference in focus fall off is however very pronounced, I'll post it up here when it's done.

 

[Jerome Marot]

First, an example of Bokeh differences. Both images are taken with the same focal length, same sensor size. The optical design is entirely responsible for the rendering of the out-of-focus zones.

​

Second: if you want to get the same effect than a large format 150mm, you won't get it by using a 50mm and stitching. You will get it by using a 150mm and stitching.

Third, using a device like this one will help stitching, especially if you have objects close: http://www.360rage.com/panorama-hardware-item.php?i=1

 

[Jerome Marot]

Are you intending to refocus for each shot. If not your plane of focus is convex and then the software has to make this rectilinear so the angles change.

Not at all. Rectilinear is the projection and has nothing to do with focus.

 

[Ben Rubinstein]

Jerome, I was using a 150mm for stitching. I was using a Nodal Ninja 5

 

[Asher Kelman]

Not at all. Rectilinear is the projection and has nothing to do with focus.

Jerome,

All the stitching software can do is get the geometry right. Rectilinear lenses allow a plane of focus with straight lines even though the distance to that plane increases laterally from the central axis. However, When that lens is swung around and not refocused that original plane is no longer followed. Rather it is at some angle less than 180 degrees. So the focus is on a new plane. Matching lines in a stitched picture and correcting angles to create a rectilinear image, does not alter the fact that the plane of focus is bent for each swing through the lens entrance pupil. This stitched picture, would have a blending of different planes of focus. This would not match the single plane of focus of a larger format lens with a larger field of view.

Asher

 

[Doug Kerr]

Hi, Asher,

All the stitching software can do is get the geometry right. Rectilinear lenses allow a plane of focus with straight lines even though the distance to that plane increases laterally from the central axis. However, When that lens is swung around and not refocused that original plane is no longer followed. Rather it is at some angle less than 180 degrees. So the focus is on a new plane. Matching lines in a stitched picture and correcting angles to create a rectilinear image, does not alter the fact that the plane of focus is bent for each swing through the lens entrance pupil. This stitched picture, would have a blending of different planes of focus. This would not match the single plane of focus of a larger format lens with a larger field of view.

Well said.

In fact, when the camera is swung around, it cannot be "refocused" on that original plane (unless we are using a "Scheimpflug-aware" panoramic camera rig).

Best regards,

Doug

 

[Ben Rubinstein]

OK here are the results. I messed up the overlap for the top layer so the stitch has a different crop. The geometry is also a bit different but that is due to the stitching software and not a change in position of the camera. Getting the software even to stitch what was a 3gb file was hard enough without trying to get the geometry perfect for a test shot. Ditto on the processing, I processed for the same feel without actually trying to match exactly, I just don't have the time at present.

Again, the camera was not moved between shots, focus was on the same leaf in both images.

First image, 5D with 50mm lens at f1.4. Second image, 5D with 150mm focal length at f3.5 stitched to provide a similar crop (or would have been if I hadn't screwed up).

As far as I'm concerned from these examples: focus fall off is more sudden with a resulting more 3D rendition, similar to the focus isolation of longer lenses but with a wider FOV due to the stitch, there is also less DOF with the stitched shot, I would need a 50mm f1.0 to match that I
would imagine! As I'd expected on both counts. The tonality is noticeably superior even in tiny web sizes, I can only imagine that it would be a lot more noticeable in a print side by side. The overall look is, to my eye, very very different. Not sure if I could explain why, it just is.

OK, next question, is it worth it. Hmmm, good question. Talking about 50+ frames to make that stitch with a full tripod setup, nodal slides, cable release, mirror lockup, etc. Shooting with my little 50mm at f1.4 wouldn't even need the tripod to be honest, that shot was at 1/2500 in the shade. The idea is that I could shoot for this look as 'walkaround' with just a body and small lens compared to all the paraphenalia of a serious shoot. The tonality is a huge plus of the stitching method but to be honest with the way I've processed that shot above, I'm not sure that it isn't going to just be photographer snobbery? Resolution at f1.4 isn't a problem, it just doesn't exist! Not that it bothers me.

I have to think about this. It could be that if I require more of this 'look' than my present lens can give me then a Rokkor 58mm f1.2 would be an admirable solution but on the whole I do like the idea of producing my vision in art with the gear I have rather than looking for magic bullets. You get to feel more of an achievement I think.

I was going to provide crops of each to show tonality differences but I'll be frank, you can't compare a 112 megapixel image to a 12 megapixel image, the sizes don't begin to work. I will say this, at 100% and with proper sharpening, the subtle tonality and rendition of the stitch is enough to cry for! In the real world however I very much doubt anyone would see the difference. I am interested however in seeing it in print to see whether there is enough difference is say an A3 print to care about. I don't have a printer but if anyone is interested in running these 2 images through their printer then I'd be very happy to share for the experiment and so that one of these pictures will find a place on someone's wall perhaps.

 

[Ben Rubinstein]

Just uploading a zoomify of each image to give a better idea. I'm very interested in your opinions as to tonality, etc.

 

[Asher Kelman]

What was the 50 1.4 focussed on and at what distance?

Then in the second, stitched picture, what was the lens focussed on and at what distance?

Also, could you use the dropper in photoshop to sample the leaves and see if the stitched version has darker leaves with more contrast perhaps?

Asher

 

[Jerome Marot]

Rectilinear lenses allow a plane of focus with straight lines even though the distance to that plane increases laterally from the central axis.

Sorry, but no. Rectilinear lenses are designed for rectilinear projection (as opposed to, say, fish-eyes) but they can have field curvature and hence a curved locus of focus. Rectilinear explains what the projection is, not what the locus of focus is.

 

[Jerome Marot]

unless we are using a "Scheimpflug-aware" panoramic camera rig.

Which is quite easy for a lens having no field curvature and a flat subject. Use this:

http://www.ebay.com/itm/CANON-4X5-EOS-ADAPTER-DIGITAL-4X5-LARGE-FORMAT-/200648368591


(a sliding adapter)

 

[Jerome Marot]

It seems to me that you are re-inventing the Brenizer method. Or here.

 

[Asher Kelman]

Doug refers to the need to tilt the focal plane by tilting the lens. A sliding adapter is the equivalent of shifting, not tilting. Or does that adapter also tilt?

Cem, Doug and Jerome, (Ben likely knows this already),

This particular Eos sliding mount for 4x5 LF cameras, goes only left to right. It's a cheap knock-off of the Camera Fusion Eos stitching Z-Y axis stitchng mount. Mine goes both directions and can easily cover 4"x10". I also have an adapter for Nikon mount cameras and a ground glass adapter to put the plane at the distance correct for the Eos Camera. Way back in 2007 I shot multiple rows of a train freehand, swinging through the imaginary entrance pupil of the lens, (well I was leaning on a tree). Next I took the same view using the Camera Fusion on Will Thompson's plastic Toyo portable 4"x5" field camera. The respective stitched images are shown in posts #s 4 and 7 respectively here.

With this Camera Fusion setup, one can have any tilt and shift one wishes and a flat field.

Asher

 

[Ben Rubinstein]

Both lenses focused on the same leaf, the big one dangling down in the middle of the frame. Eyedropping leaves wouldn't tell us anything, the images were not processed the same so they won't match for density, not that it would tell us anything about tonality anyway.

I've uploaded zoomify's of both frames:

www.studio-beni.net/Psalms.html
www.studio-beni.net/Psalms2.html

Both gently sharpened.

 

[Jerome Marot]

Doug refers to the need to tilt the focal plane by tilting the lens. A sliding adapter is the equivalent of shifting, not tilting. Or does that adapter also tilt?

Doug cited the Scheimpflug rule. The mathematical conditions of Scheimpflug are also met if the image and object planes are parallel and orthogonal to the optical axis, hence a sliding adapter fulfills the conditions of Scheimpflug. And, actually, given the conditions of Asher's post (a plane of focus) and Doug question about "a Scheimpflug-aware panoramic camera rig", also the sole solution to the stated problem.

Sorry to appear pedantic, but when Doug referred to "a Scheimpflug-aware panoramic camera rig" I had visions of complicated setups with movable film planes for a few seconds, until I realized that the sole solution is indeed a sliding adapter. And I thought that giving the solution would be appreciated.

The adapter does not tilt.

 

[Jerome Marot]

Therin lies the rub. Why would one need this stitching method if one would already have a 4x5 camera? Ben needs to solve his problem using his 5D. This is a non-solution. Such misinformation obfuscates the discussion.

I don't think it obfuscates the discussion. A second hand 4x5 camera and sliding adapter is not considerably more expensive than a spherical panorama head and the result is the same: photographs on a 5D.

 

[Asher Kelman]

Therin lies the rub. Why would one need this stitching method if one would already have a 4x5 camera? Ben needs to solve his problem using his 5D. This is a non-solution. Such misinformation obfuscates the discussion.

I wouldn't call Jerome's smart suggestion, "Misinformation" that, unfortunately suggests motivated provision of misleading directions. Actually, he's entirely correct if one uses the original Camera Fusion sliding adapter which covers 6x12 easily.

Asher

 

[Doug Kerr]

Hi, Jerome,

Sorry to appear pedantic, but when Dough referred to "a Scheimpflug-aware panoramic camera rig" I had visions of complicated setups with movable film planes for a few seconds, until I realized that the sole solution is indeed a sliding adapter.

That is a classical form of what I had in mind. Sole solution I wouldn't be so sure of.

Of course its execution could be more or less complicated. Asher's rig is one of the more direct, but it works because the whole camera is much larger than the actual frame size of the taken images.

There could be rigs in which the entire camera swiveled while both the front standard and backhouse swung in proper Scheimpflugian synchrony, for example.

Sorry if I let anyone down by not providing an extended dissertation on such. Perhaps after lunch.

Best regards,

Doug

Perhaps I was not the proper person to respond.

By way of identification, this is one example of Dough:

 

[Jerome Marot]

If one swings the camera for a few degrees, the object plane is no longer parallel to the film plane and one has to tilt the lens.

The camera must rotate around the lens (the entrance pupil, actually) to keep the perspective. This means that the lens is rotated too.

 

[Jerome Marot]

There could be rigs in which the entire camera swiveled while both the front standard and backhouse swung in proper Scheimpflugian synchrony, for example.

I don't think that the images would match, then. You would have different magnifications at the seams.


(I corrected your name. Sorry about that.)

 

[Asher Kelman]

How the Camera Fusion adapter works with LF lenes.

Guys,

Let me set this record straight. With the Camera Fusion adapter one uses neither film nor Canon lenses! The whole idea is to be able to select an optimal plane of focus with a large format lens and a wide single field which is sampled by sliding any lightweight Eos DSLR over the field in and takng rows of overlappng digital mages.

Ben already knows about the Camera Fusion system, LOL since 2009 The system uses any lightweight Canon or Nikon DSLR and a large format lens which covers the entire field of view. The Eos camera simple slides along rows to progressively sample the single mage plane chosen with the selected tilt, shifts and rise/fall of the front and rear standards of the 4x5 camera.

I was only pointing out the Jerome's suggestion was actually perfectly valid as an approach to solving plane of focus issues. In fact, years ago, I had Ben contact the MFR of Camera Fusion. With Camera Fusion one uses digital, and the 5D is more than enough. A digital Rebel would be fine too. One makes any adjustments in tilt/shift that will put the entire single flat plane of focus exactly where it's needed. I merely added my references to the system to make the record complete and point people away from the eBay-link of the inadequate knock-off of the Camera Fusion adapter. I'm not at all concerned about Ben being led astray, as he already knows the system backwards! If he needed a LF camera that could be corrected fast!

The thread serves to answer both the O.P.'s question and also should be complete for the record and future reference.

It turns out to be a simple choice that one can keep in mind if one has plane of focus issues not easily met in some simpler fashion. We've previously sent a LF camera to solve a problem like this!

Asher

 

[Doug Kerr]

Hi, Cem,

Well, I prefer the term non parallax point of the lens as the entrance pupil is not really where it is at.

But it is (as I have indeed explained).

Best regards,

Doug

 

[Doug Kerr]

Hi, Jerome,

I don't think that the images would match, then. You would have different magnifications at the seams.

Quite so. There would be further movement required (probably along the bed).

The result would in fact be geometrically equivalent to the "sliding" implementation, I think. So I agree as to the uniqueness of the needed geometry - just not of a "sliding" execution of it! (I guess "translation" of the filmholder is what we really need to speak of, which does not imply any mechanism.)

Thanks for your inputs

Best regards,

Doug

 

[Asher Kelman]

Asher,

I've already discovered and corrected my own faulty assumptions due to unfamiliarity with this adapter. However, one still needs a LF camera. I keep on repeating myself but is this not exactly the issue? That we want to mimic LF usng a 35mm camera? For the rest, I agree.

Cem,

One is not "mimicking LF", merely doing LF photography. We're just not using film. We're exploitng the carefully adjusted huge and "seemingly endless" plane of focus that a large format camera lens so readily provides. This is actually no longer 35mm photography, rather we're "borrowing" the digital sensor to get the LF picture.

Asher

 

[Ben Rubinstein]

I seem to have missed some fun!

OK, why not just shoot LF. Been there done that. Don't want to do it again. A 5D with a 50mm lens (for composition) and 150mm lens (for shooting) with a NN5 fits in a very small bag. It's light. I already own everything but the 150mm which KEH are selling for $45 at the moment.

Forget view camera focusing or composing using a DSLR without LV. Been there, it's not pleasant. My 5D doesn't have LV. A tripod for a view camera with a DSLR hanging off the back needs to be bigger than my nice light CF 2 series Gitzo.

Basically I'm trying the 'easy' way. It is pretty easy, I shot all the frames for the stitch in just 4 minutes and setup took a minute. Couldn't do that with a stitching back on a LV camera, heck after 4 minutes I'd still be trying to find out where on earth my left hand got to under the darkcloth as I'd lost it! No the stitching isn't easy once you get home but let's face it, it's still easier IMO than film developing, scanning and spotting. Heck of a lot cheaper too.

This was just an experiment, would the tonality of the stitch win me over compared to just shooting wide open. I had no desire to start shooting with a view camera or actually investing any more than that $45. I've done the experiment, I'm now musing on the results as to whether I'm even going to bother with that $45, I'm not sure the difference is worth it for anything other than my snobbery about tonality which few these days even understand nevermind will appreciate enough to make me bother. Especially when shooting with single shots gives the ability to include people in the frame. Now what I really wish I could afford is a 1Ds3 again, the extra resolution with the incredible tonality that body gives would be very nice. If I can't just chuck $45 about at the moment I doubt I can buy into cameras like that just for my tonality snobbery!

 

[Ben Rubinstein]

It seems to me that you are re-inventing the Brenizer method. Or here.

Not 're-inventing', using. I made no claims whatsoever for having invented the method and my work with it was indeed inspired by work using the method that Brenizer made popular but far from invented whatever flikr thinks! I have been trying to adapt it to provide the same FOV of the 50mm lens perspective that I love so much.

 

[Ben Rubinstein]

I keep looking at these pictures, trying to work out whether I like the look of the stitched version. There is a glow around the focus point and a drawing to the f1.4 version which the stitched version just can't match for all that it has less DOF and more tonality. Finding it hard to describe exactly.

 

[Bart_van_der_Wolf]

It seems to me that you are re-inventing the Brenizer method. Or here.

Hi Jerome,

As a veteran in stitching (I started by stitching film scans before digital cameras became common), I have to say that I've never heard about a "Brenizer method" before. I somehow doubt he 'invented' the method, although he may have helped to make it popular. Perhaps you used the term in the latter sense.

Most people only consider wide panoramic vistas when talking about stitching, but I've been using stitching for ages on regular scenes where I wanted to increase the resolution by shooting with longer focal lengths, and stitching to make up for the required Field of View. The use of longer focal lengths will reduce the apparent Depth of Field, and as such that can be purposely used to create an extremely narrow DOF, essentially no different from using a large format camera (but potentially with even narrower DOF). No invention required, it's just a fact of life with stitching and longer focal lengths.

Brenizer does use it successfully as a creative element, and adds to the effect by including potentially non-stationary subjects/people in the stitch. I would rather call it a method used/exploited by Brenizer than suggesting that he invented it (he is cited to having spent a lot of time reinventing the wheel though).

Cheers,
Bart

 

[Doug Kerr]

Hi, Asher,

Ben already knows about the Camera Fusion system, LOL since 2009 The system uses any lightweight Canon or Nikon DSLR and a large format lens which covers the entire field of view. The Eos camera simple slides along rows to progressively sample the single mage plane chosen with the selected tilt, shifts and rise/fall of the front and rear standards of the 4x5 camera.

Thanks for the concise summary of this "scheme".

As Jerome points out (and of course I paraphrase), this performs in the most direct way the dissection of a larger format image into multiple smaller format images, which (if digital) we can then combine using available "stitching" tools.

As Asher points out, once we take this approach, then the overall optical properties of the "rig" are identical to those of the same camera with a full-frame film holder ("full frame" here meaning, as it ought to always, the normal largest frame size of the camera "chassis" involved). [I assume here that the journey of the small camera fully maps the full frame of the base camera; perhaps in practice it doesn't exactly.]

Thus, with a certain lens in place, depth of field considerations (based on criteria pertaining to the size of the composite image, of course) and the matter of providing for the "plane" of perfect object focus to be located and oriented as we need, pursuant to the principles of Scheimpflug, using the movements of the base camera, work just the same way they would with that camera (and lens) with a full-fame film holder.

Very clever, and I would assume very workable.

Best regards,

Doug