Image Circle of various lenses

[rjpierrard]

<p>Hello,</p>

<p>I've looked through the previous questions regarding image circles, but my question is unfortunately specific.</p>

<p>I can't seem to find any reference to image circle of specific lenses by the manufacturer - I posted the question in another forum regarding smaller format lenses, but the replies there were that the manufacturer doesn't tend to post these details.</p>

<p>I'm specifically interested in the image circle dimensions for:<br>

Schneider Super Angulon XL 58/5.6 for 4X5<br>

Caltar II NC 65/4.5 for 4X5<br>

Nikkor SW 75/4.5 for 4X5<br>

Pentax 45/4 for 6X7cm<br>

and Mamiya RZ ULD 50/4.5 for 6X7.<br>

(I'm also considering the Schneider Super Angulon 47/5.6 for 6X9cm, but I know the image circle to be 123mm from the website.)</p>

<p>The reason for asking is I'm interested in using shift to expose the full image circle over several digital captures using a FX DSLR, and would like to know the amount of exposure (and hence final max size) of any stitched capture I could make.</p>

<p>I plan on mounting the lens on a 4X5 view camera to be able to use the full functionality of shift, etc (may also get into tilt later). I realize this requires light-proofing the camera, and I'm working on fleshing out an adapter to the DSLR for this purpose.</p>

<p>The reason I'm considering the smaller format 6X7cm lenses is mostly that I enjoy wide angle captures, and would prefer fewer exposures be required to attain that wide angle - the range of 80-100* diagonal FOV is my preferred view, at least in this capacity.</p>

<p>If someone could point me in the direction of some nice 6X9 format lenses as a mid-ground between the 6X7cm and 4X5", that may ease some decision making.</p>

<p>With regards to the image circle dimensions, if there is a database for larger format lenses that supplies this information, it would be greatly appreciated.</p>

<p>Thanks very much!</p>

[leighb]

<p>Schneider Super Angulon XL 58/5.6 - IC = 166mm @ f/22<br /> Nikkor SW 75/4.5 - IC = 200mm @ f/22</p>

<p>IC specs are unrelated to the intended format.</p>

<p>The datasheets for these lenses are readily available online. Try Google.</p>

<p>No info re the other lenses.</p>

<p>- Leigh</p>

<p> </p>

[rjpierrard]

<p>Thanks, I hadn't been able to find any details earlier, I suppose as I was looking for smaller format lenses.<br>

Do you know of any datasheet for medium format (67, especially)?</p>

<p>Regarding image circle size, I know it has no bearing on the intended format, but some lenses are designed with larger formats in mind, eg Schneider's XL and XXL series.</p>

[bob_salomon]

<p>The image circles as well as MTF, distortion and color curves are all posted on Rodenstock's web site and are easily downloaded.<br>

Basically lenses made for medium format or smaller cameras do not cover much more then the format since the lens and the back are fixed in relation to each other and do not work like a view camera. The only exception are the PC or T/S lenses for these formats that must have a larger circle.</p>

 

[mike_earussi1]

<p>Having owned the 45mm lens for the 6x7 I can tell you that it covers 6x7 and that's it (and that's at f11).</p>

[michael_briggs2]

<p>As Bob posted, Rodenstock has info on current lenses at their website. Schneider has info on current and past LF lenses at their website. There are compilations at http://www.largeformatphotography.info/lenses/. For an older Caltar you may have to deduce the actual manufacturer and look up their specs. Coverage specs were rarely given for camera-dedicated, fixed-position MF lenses since the users didn't need to know this information.</p>

[john_shriver]

<p>You will probably be unable to use anywhere near the full image circle stitching with a DSLR, since the lens mount of the camera will start to cast a shadow on the sensor. (Game over.)</p>

 

[friedemann_pistorius]

<p>There are two different Super-Angulon 47/5.6 lenses with different image circles:</p>

<p>Super-Angulon 47/5.6, image circle 123mm at f22<br>

Super-Angulon XL 47/5.6, image circle 166mm at f22 (same as the XL 58)</p>

<p>www.schneiderkreuznach.com (Germany) or www. schneideroptics.com (USA)</p>

<p>Consider Fujinon-SW lenses too, outstanding performance (I have a Fujinon-SW 65/5.6, image circle 170mm at f22).</p>

[jim_jones3]

<p>In addition to the lens mount casting a shadow on the sensor as John noted, mounting the camera to a view camera back will preclude focusing such short focal length lenses on infinity. Perhaps a mount can be improvised to mount the lens directly on the camera. However, there is only a few mm between the rear element of my S-K f/8 65mm lens and a Nikon DSLR lens mount for improvising such an adaptor. It seems simpler to use the coverage of WA lenses by shooting and scanning 4x5 film</p>

[bob_salomon]

<p>The diagonal of a 35mm full frame camera is 44mm. So a normal lens is a 44mm lens. Using analog lenses on a view camera with this short a focal length will prove very tricky as you have to position the sensor to be at the flange focal length of the lens to be able to reach infinity. That means that you are going to attach the camera body, probably to a lens board, and that will push the sensor away from the lens.<br>

The FFL of a 47mm SA XL in Copal shutter is 59.1mm so from the rear surface of the shutter to the sensor plane in your camera you must be at 59.1mm to focus at infinity. If you are using the original 47mm SA then the ffl; is 51.6mm. And then you only have a normal lens, with a hot spot. If you want to use the 38mm XL then the ffl is 52.1mm.<br>

On the othe hand the ffl for the Rodenstock 40mm 4.0 HR Digaron-W is 69.5mm, the 28mm HR Digaron-S is 53.1mm and the 23mm is 44.8mm so you can more easily reach infinity with some lenses like these. But doing it with a 35mm SLR would not be the best or easiest way.</p>

[rob_tucher3]

<p>Years ago I had a shift adapter that allowed me to mount my Pentax 67 lenses on my Nikon F4s. I have been sitting here for a long time trying to remember the name...Zork or something like that. It was a fabulous device and gave me shift capability with lots of movement (6x7 coverage on 35mm), and was well made too. A search of eBay might net you one if you can think of a key word to look for. </p>

[friedemann_pistorius]

<p>http://www.zoerk.com</p>

[rjpierrard]

<p>Thanks, I've already had a look at Zoerk adapters. I dislike the panorama shift adaptor as it only allows for shifting in the horizontal direction - I would be unable to do a 2X2 or 3X3 stitch with a lens that has the required image circle due to the limited shift. The pro version with full movements is out of my price range.<br>

@Jim Jones: Thanks for the observation, I'll look into the geometry of mounting various format lenses to work with a DSLR.<br>

@Bob Salomon: Thanks for the detailed response! By analog lens, you're referring to 4X5" or other view lenses? I think I need to do some more research on the specifics you mentioned.</p>

[bob_salomon]

<p>Research away:<br>

http://www.rodenstock-photo.com/en/main/download/professional-photography/</p>

[John Crowe]

<p>I have no idea what your budget is, but I do know some of those lenses are pretty expensive, particularly the XLs. My perspective comes from having shot an SA 65mm f8 on 4x5 Velvia, and having considered shooting either the 47 XL or 58 XL on 4x5. I'm not thinking to heavily mathematically right now but the problem is that these are not terribly wide on an FX sensor. At 2x3 (about 6x9) capture these are at best about a 26-30mm equivalent to FX. The medium format lenses you discussed are not even wideangle in FX.</p>

<p>Also note that medium format and large format lenses do not resolve as well as FX lenses. Now you would be stitching FX images to negate this lack of resolution a bit, but I still think you would be well under the abilities of the XL lenses at only 2x3, they need the full 4x5 image area so that they do not require as much enlargement as a smaller format.</p>

<p>In the spring I sold my 4x5 system and switched to a Canon 5D II and Canon EF 17mm f4 L TS-E. I am able to stitch to create 24mm x 60mm or 36mm x 48mm images. I think I could gain another millimetre or two by shifting at 45 degrees as well. This is getting into the 42 MP range and final image size is about 250 MB. At 36mm x 48mm it is not far from current medium format digital backs. In this case, since I am actually going beyond the FX view of a typical 17mm lens, final image view, with full stitching, is more like a 12mm lens. This lens works well with converters and Canon also has a 24 TS-E, 45 TS-E, and 90 TS-E for regular wideangle focal lengths and normal focal lengths when stitching. Nikon has some more affordable options for stitching with their used 28mm PC and 35mm PC lenses from the film days. I mention this as a possible alternative to trying to mount larger fomat lenses and stitch. I prefer the ultrawide angle range and would have to be stitching the full 4x5 image of a 47 or 58 XL to achieve a similar view of the 17 TS-E on FX. </p>

<p>If you pursue the large format idea I am pretty sure there are already lensboards made for mounting Canon and Nikon bodies. Perhaps they are only made for prohibitively expensive systems though. Sinar comes to mind as one possibility.</p>

<p>Shifting and stitching is a very interesting pursuit. I have been so blown away by the capabilities of Photoshop Merge that I am not convinced that properly shifted lenses are absolutely required. My experiments continue. By the way, I experimented with a dozen on-line stitching sytems and found Photoshop Merge to be far and away the best, but you must experiment with settings and in my case, either due to computer limitations or PS limitations with files from a 21 MP camera, I can only stitch two or three images before having to restart PS.</p>

<p>Good luck, let us know how you make out.</p>

[q.g._de_bakker]

A 47 mm lens on 6x9 (56x86 mm in my Sinar rollfilm back) is the equivalent of a 20 mm lens on 35 mm/FX format. The 58 mm on 6x9 is equivalent to a 24 mm lens on 35 mm/FX format. A bit wider than the 26-30 mm you mention, John.<br><br>That bit about MF and LF lenses not performing as well as FX format lenses needs substantiating, is not true per sé (depends on what lenses you are comparing), and sometimes the opposite is true.<br><br>Kolor's Autopano Giga is a great stitching program.

[q.g._de_bakker]

Oh, and the 47 mm on 4x5" has the same horizontal angle of view (even wider vertically) as a 14 mm lens on 35 mm/FX format. The 58 mm on 4x5" is about the same as a 17 mm on 35 mm format.<br>So no need for stitching <i>" to achieve a similar view of the 17 TS-E on FX"</i>. If anything, you need to crop (both vertically as horizontally).

[rjpierrard]

<p>@John Crowe and Q.C de Bakker: the point of this setup would be to stitch multiple images together, forming an effective sensor size close to whatever image circle the lens I'm using has. As a result, I'd be using nearly the full image circle, and so result in a total FOV close to the native FOV of the lens on it's native format.<br>

I've looked into the shifting and stitching using either a TS/PC lens, or a shift adapter, but both options seem to have more limitations than using a lens with a huge image circle in comparison.<br>

I currently use Autopano Giga2 as my stitching software, and designed my computer system to allow for large stitching projects.</p>

<p>Given my options on multi-exposure stitches (panorama, panorama with pano head, TS lens, shift lens adapter, or large format lens), I think I'm going to go with the panoramic head.<br>

I've enjoyed my foray into large format lenses, and it's very possible that I'll get into LF eventually, but not with my current needs/interests.</p>

<p>Thanks for all your help!</p>

[John Crowe]

<p>Q.G., you have missed my actual comparisons. The poster spoke of utilizing these lenses for 2x3 images, not 4x5, so that is the basis of my 20-36mm equivalence. So by my approximation the 47 and 58 would be 10-18mm equivalence, <em>if</em> you were using them on 4x5. That is my point. To get to the 12mm shifted equivalence of the 17 TS-E on 36mm x 48mm or the unshifted 17 TS-E on FX you would have to record the entire 4x5 image projected by the 47 or 58. For my ultrawide desires this would be a lot of stitching, assuming that the FX body opening does not interfere with the passing of light from the 4x5 lens.</p>

<p>I've been crunching more numbers, drawing image circles to check format coverages, and even if large format or medium format lenses equal or exceed FX lenses in resolution it still boils down to a heck of a lot of stitching to get to ultrawide angle imaging. Depending on the photographer's intended subjects this could be a challenge even with the best stitching software. My maximum stitch has been 3 images to create one file, and even with the images only seconds apart, I have had some challenges with stitching to overcome moving branches, clouds, and shadows. Having to stitch 15 to 30 consecutive images, to create an ultrawide landscape for instance, could be problematic. For more conservative fields of view in the 28mm to 40mm FX equivalency range the large format route may make sense for photographic situations in which the scene may be changing.</p>

[q.g._de_bakker]

John,<br><br>[QG] <i>"A 47 mm lens on 6x9 (56x86 mm in my Sinar rollfilm back) is the equivalent of a 20 mm lens on 35 mm/FX format. The 58 mm on 6x9 is equivalent to a 24 mm lens on 35 mm/FX format. A bit wider than the 26-30 mm you mention, John."</i><br><br>and:<br><br>[QG] <i>"Oh, and the 47 mm on 4x5" has the same horizontal angle of view (even wider vertically) as a 14 mm lens on 35 mm/FX format. The 58 mm on 4x5" is about the same as a 17 mm on 35 mm format."</i><br><br>Not [You] <i>"20-36 mm"</i> and [You] <i>"10-18 mm"</i>.<br><br>See?<br>;-)<br><br><br>Let's continue to root out inaccuracies:<br><br><i>" To get to the 12mm shifted equivalence of the 17 TS-E on 36mm x 48mm or the unshifted 17 TS-E on FX [...]"</i><br><br>A 17 mm on double 35 mm format/FX is the equivalent of (should not be a surprise) 17/2 = 8.5 mm. Not 12 mm. If you only get a 12 mm's worth, that would mean that you would have 14 mm overlap, i.e. would be creating a 36 x 34 mm stitched result.<br><br><i>" it still boils down to a heck of a lot of stitching to get to ultrawide angle imaging."</i><br><br>47 mm lens, two (!) 6x9s, 10 mm overlap, and you get a horizontal angle of view the same as that of a 10 mm lens on 35 mm/FX format. One (!) single stitch, and 119 degrees of the landscape in front of you is 'in the can'.<br>Vertically, the angle of view will then still be the same as that of a 20 mm lens on 35 mm/FX format. If not wide enough, two more stitches, same overlap, and that vertical angle of view is increased to that of a 11 mm lens on 35 mm/FX format (93 degrees).<br>I don't know of any stitching software that would be challenged by that, but would readily believe there are such programs. There also is - i know - software that is not.<br><br><i>"Having to stitch 15 to 30 consecutive images, to create an ultrawide landscape for instance [...]"</i><br><br>As in: a 20 mm on 35 mm/FX format isn't quite "ultrawide" aready? O.K.<br>Those two 6x9s stitched with 10 mm overlap, exposed through a 47 mm lens will capture almost, but not quite, 120 degrees horizontally. 6 of them stitched together will leave a gap of about 4 degrees on the full 360. Which could be remedied by reducing the overlap to 5 mm.<br>6, instead of 15 to 30, and you cannot get any (ultra-) wider already.

[q.g._de_bakker]

Robert,<br><br>I think you will only achieve in making life more difficult.<br>Those large image circle lenses are all made for large format (except the shift lenses made available by the producer of your DSLR), and cannot be adapted to work on SLRs. If you want ultra wide, just put a 47 mm SA XL on a cheap 4x5" camera, put a 6x12 rollfilm back behind it, and shoot away (or a 6x9 back and stitch two images. Use the shift feature* of the camera to position each - one left, one right, with a bit of overlap.) Couldn't be simpler.<br><br>* Shifting the film inside the image circle keeps perspective constant, i.e. you will not need expensive gimbles to move and keep the entry pupil of the taking lens in the correct spot.

[John Crowe]

<p>I give up. Q.G. the poster and myself are talking about stitiching using a 35mm format DSLR also known as FX. You need to re-read the question.<br>

"<em>The reason for asking is I'm interested in using shift to expose the full image circle over several digital captures using a FX DSLR, and would like to know the amount of exposure (and hence final max size) of any stitched capture I could make."</em><br>

Good-luck, Robert.</p>

[q.g._de_bakker]

John,<br><br>You said some things that are just not right. All i did is address what you said and correct that.<br><br>And once again:<br><br>[You] <i>"the poster and myself are talking about stitiching using a 35mm format DSLR also known as FX"</i><br><br>[You] <i>"The poster spoke of utilizing these lenses for 2x3 images, not 4x5, so that is the basis of my 20-36mm equivalence"</i><br><br>See what you are doing here?<br>You do that quite a lot, saying things that are not right.<br>And when you do and get caught, the civil thing to do is admit your error. And not (note: not) suggest that the one who points them out to you is stupid.

[leighb]

<p>You cannot make an image that looks "right" using the small sensor and lens shift technique under discussion.</p>

<p>When you take a real photograph, all light impinging on the film appears to emanate from a single point, called the "rear node" of the lens. <br>

This is true regardless of whether or not the lens is shifted.</p>

<p>If you try to take multiple small images by shifting the lens, each image has a different rear node location. The brain will not be able to resolve the resulting composite image properly.</p>

<p>You can confirm this problem using a very simple two-exposure test:<br>

Find a long straight street. Stand on the sidewalk on one side and take a photo looking straight down the sidewalk.<br>

Now cross the street, point the camera straight down that sidewalk and take another shot.</p>

<p>Now stitch the two together. There will be a large area of overlap, so stitching will not be a problem.<br>

The resulting image will look very weird indeed.</p>

<p>This is admittedly an extreme example, but it illustrates the problem quite effectively.</p>

<p>- Leigh</p>

<p> </p>

[rjpierrard]

<p>I'll deal with this simply:</p>

<p>I've reconsidered my question and, as mentioned, have decided on a panoramic head rather than shift-stitching. In this I agree with QG de Bakker that this escalation of a simple principle is excessively complicated, and a pano head would be much easier to deal with, and even cost less.</p>

<p>QG de Bakker and John Crowe: you're both talking about different aspects of what I was planning on doing: using a Digital FX = 35mm sensor with a medium/large format lens, and shifting the lens around to utilize closer to 100% of the image circle. I was referring to using the image circle between a 6X7cm and 4X5" lens, and shifting in the same way a TS/PC lens does, just with more movements and exposure. As a result, the crop factor would be calculated according to:<br>

Crop factor = square root [(larger sensor area) / (smaller sensor area)].<br>

Example: using a FX lens on Nikon DX format: sqrt[(24*36)/(15.8*23.6)] = 1.522<br>

If using a lens with an image circle of 6X9cm = 101mm diagonal (56*84mm area), and do a 2X2 exposure at 25% overlap, the effective sensor size is 42*63, and the crop factor is sqrt[(56*84)/(42*63)] = 1.333.<br>

Thus a 47mm lens would look like a 47*1.333 = 63mm lens, and would have a diagonal field of view of: 77.7* (compared to the theoretical FOV of 94.1*, if the whole image circle was used).</p>

<p>Because in shifting the lens there is movement that is not around the nodal point, I agree with Leigh B. that there is the possibility for problematic images. However, the degree that this becomes a problem is highest when the subject of the picture is closer to the camera. Given that I am doing landscape work with what I was considering this setup for, any errors of this sort are extremely minimal, and I would suspect wouldn't be noticed at all.<br>

As a side note though, there are programs where image stitching with multiple camera positions works perfectly without stitching errors, but can (as Leigh mentioned) result in some very weird looking results.</p>

<p>Thanks for all your help, but I think the matter is closed.</p>