MF lens comparison to LF lens

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Hi, I'm thinking to step up to LF buying a Toyo vx125 camera and using it with a roll film back. My question is: a 4x5 Large Format lens projecting on 6x7cm roll negative, would it produce different quality (resolution, acutance) that I would get with a traditional medium format camera lens? Please, imputs on this issue are very much appreciated. Thank you.

-- mario abba (maab@nyc.rr.com), July 10, 2000

Answers

Yes, it would.

-- Bill Mitchell (bmitch@home.com), July 10, 2000.

I think, if picture sharpness is your only concern, go with MF. MF is much more practical and optimized. But LF will allow for many corrections and if you use modern lenses at selected openings and work on your GG focus, sharpness will be plenty for most uses. With the VX, an insert type back is a must.

-- Paul Schilliger (pschilliger@smile.ch), July 10, 2000.

Mario, I wonder why you are considering using a roll film back on a LF camera, especially the VX125 (expensive!!) and with a 6x7 format? I would be inclined to either use 4x5 sheet film or use a 6x12 back at the very least, or simply get yourself a MF outfit. IMHO it seems a bit of a waste of all the movements offered by LF if you are trying to cram them onto a 6x7 neg. I always find it easier seeing the effect of movements on a large screen especially tilt. Good luck!! Regards Paul

-- paul owen (paulowen_2000@yahoo.com), July 10, 2000.

Paul, thank for your posting. I'm interested in large format camera because of the movements that I cannot achieve with my Pentax 67. I like to shoot in MF at least at this moment. And in the future who knows, at this moment working with sheet film it's not for me. I read somewhere that large format lenses are optically inferior regarding sharpness and acutance compared to MF lenses, so this is the only dilemma that keeps me from my final decision. Although I'm giving some thoughts to the Fuji GX680 as an alternative, at least until I will have a more precise idea about the degradation quality with LF lenses compared to the MF Lenses. I mention 6x7 because I was making a comparison with my pentax, for me the ideal is 6x8 cm but if I'll use the roll back on the LF I would certainly go for the 6x9 in absence of 6x8. Thank you for helping.

-- mario abba (maab@nyc.rr.com), July 10, 2000.

Have you considered one of the MF view cameras which have a full complement of movements? Two that come to mind are the Arca Swiss F 6x9 or the Linhof Technikardan 23S. Hasselblad also has their Arcbody which has a limited range of movements.

You might try renting a LF setup with a roll film back, and doing your own comparisons.

-- Larry Huppert (Larry.Huppert@mail.com), July 10, 2000.



At least a technical answer to you question is discussed by Chris Perez here: http://www.hevanet.com/cperez/resolution_limits.html In summary he says that for a resolution of 7 lines/mm on the final print, a 6X7 system will require 51 lines/mm for a 16X20 inch print or 25 lines/mm for an 8X10 inch print. Meaning it would be pretty easy to do an 8X10 with a LF lens, but your slightly on the margin for a 16X20 and will have to use a good LF lens at the more optimum apatures.

-- Roger Rouch (rrouch@msn.com), July 10, 2000.

Mario,

I use a 6X9 roll film back quite often on my LF camera with a mix of Nikor and Schneider optics and am hard pressed to see a drop off in optical quality when compared to my 67 or 645. If there is any loss here it is more than made up for in your ability to have more control over perspective and DOF when compared to MF.

However, I also would question your decision to go with a LF camera if you have no intention of shooting sheet film. The suggestion to look at the MF cameras that have movements is a good one. One other thing about roll film backs, particularly a 67 back, on LF that you may not have considered is the fact that wide angle work becomes more difficult. Since you are using only the "center" of the image projected on the GG your 90mm lens is not longer giving you a 90mm image, so to speak. To get a comparable field of view on the film you would probably have to use something like a 65? (Someone correct me if I'm wrong on the focal length here). Does the camera you're considering readily take a extreme wide angle, or do you need bag bellows and/or recessed lens boards?

What is it about sheet film that concerns you? If it has to do with dust and the weight of holders you might want to consider quickloads. If it's cost then that's another matter entirely. Working with sheet film can seem a little intimidating at first but once you've done it for awhile it becomes second nature.

-- Mark Windom (mwphoto@nwlink.com), July 10, 2000.


Thank you to every one for your time and for your precious help.

From the information that you kindly shared with us I understood that a good LF lens will not degrade the already excellent quality that I have been getting with the Pentax 67 lenses.

The link that Roger suggested shows that some study were performed to check the resolution of MF/LF lenses and is clearly understandable that modern LF lenses are up to the job. So if I use a Nikkor (for example) that has a resolving power of at least 60 l/mm I have good chance to get a quality 6x7 negative known to me from the pentax lenses.

At the question why I would use roll and not sheet: it's just because the way I like to shoot; several shoots for each image, ver+oriz, zone placement, etc.. I like to see the image through the viewfinder which helps me to create and visualize the final image. It scares me to think that I have to compose upside down, too many things to do before shooting could take away some of the concentration from me. That's what I'm concerned about LF but I I'm going to give a try so that's way it would be friendlier starting with a Toyo vx125 (which is apparently a very capable camera working with a 65mm or 57mme and easier and faster then average to use) and roll film back (6x9). Still if I think that I have to place and replace each time the film back between triggering.... I'm used to look through the viewfinder very often between shots, it helps me to improve the angle, or change the composition or something else that always come up. I guess I could do this with the LF as well but with some energies spent to the technical side more then I'm used to.

Thank you very much for your help. Best regards, Mario.

-- mario abba (maab@nyc.rr.com), July 10, 2000.


I'd like Bill to expound on his resounding "yes,it would".

A lens is a lens is a lens, and only a lens, in my book. Whether it's designed to cover 35mm or 20x16, it brings light to a focus, full stop (if you'll pardon the pun). It's a tool. Any other attribute you ascribe to it is pure wishful thinking, like those silly so-and-sos who think their car has a personality.

-- Pete Andrews (p.l.andrews@bham.ac.uk), July 11, 2000.


Mario: You mentioned being afraid of the "upside down image" on the ground glass. Fear not. After a very short learning curve, you will find that the upside down image actually improves composition. LF is for studied work, where you take your time making the image. After a while, you may, as I have, arrive at the point where an upright image looks strange. Don't worry about lens quality. You will be using the center part of the len's image, which is the sharpest. Even the older LF lenses are blazenly sharp in the center.

-- Doug Paramore (dougmary@alanet.com), July 11, 2000.


I went through the same "decion-making-process" myslef, until I got tired of staring at MTF charts and simply bought an ARCA 6x9 with Schneider and Rodenstock lenses. Compared to my Hasselblad lenses: if I view the negative under a microscope, the medium format lenses are somewhat sharper and have somewhat better resolution at their sharpest focal point. As soon as I apply lens tilt to increase DOF however, the view camera "blows away" what I can achieve with my Hasselblad, and I do not need a microscope to appreciate the difference - it's so obvious!!! From now on, I use my Hasselblad strictly for hand held photography - if I have the time to setup a tripod, I'll use the 6x9 (which I like MUCH better than 6x7!)

-- Andreas Carl (andreas@physio.unr.edu), July 12, 2000.

Have you actually examined the two side by side under a microscope? What power magnification was required to see the difference? . . . One thing that's lost in the medium format - large format lens resolution comparison is overall "look" of the lens, which, to me includes color rendition, rendition of subtle tonal ranges, and that final "X" factor, meaning that when I use a particular lens in actual conditions do the results on my light table often cause me to react by saying, wow, what an image. On all of these counts, using the latest Schneider and Rodenstock lenses in 6 x 9 format, the results are superb. . . . The one area where I've been a little disappointed with large format lenses, and, in a particular, I've noticed this with my Rodenstock APO Ronar 240 mm f9, which otherwise is a wonderful lens, is "bokeh," meaning how pleasing do the out of focus areas look. I suspect that this is related to the design of the diaphragm -- i.e. how many blades are used, more being better, if you believe the 35 mm lens marketing hype.

-- Howard Slavitt (info@naturelandscape.com), July 12, 2000.

Differences were very obvious at 100x magnification (corresponding to 200x300 inch prints!!!) - but I didn't check what was the LOWEST magnification were I could see a difference. I completely agree with you, 6x9 slides from Rodenstock or Schneider lenses are superb and any "absolute" advantage a medium format lens might have is negated once you use lens movements to tilt the plane of focus. For what it's worth: I specifically compared the Hasselblad CF 100 T* and the Schneider XL 110 - both being fantastic lenses!

(I have not yet been able to discern the more subtle differences like color rendition or tonality - at least in my hands differences in film freshness, film processing and exposure accuracy within 1/3 f- stop tend to outweigh these subtleties...)

-- Andreas Carl (andreas@physio.unr.edu), July 12, 2000.


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