Quick questions about the Mamiya 7II

[romain_j.]

<p>Hello everyone,<br /><br />As some here know, I use a Mamiya 7II with 80mm F4 and I have some questions:<br /><br />- Concerning the problems of diffraction of the objective, I heard that the best are from F4 to F11. What do you think of F16, the loss of quality is really important? Many saythat F22 is frankly very bad. I'd like to hear your opinions.<br /><br />- On one of my contact sheets seems a strange thing (the diaphragm), you know howthis happened? (see photo attached)<br>

<img src="http://img151.imageshack.us/img151/654/sanstitre1vo.jpg" alt="" /><br>

<br /> - Finally, I'll buy a big stock of films, including films 220, the camera works well withthis type of movie? No bad experiences?<br /><br />Thank you<br />Roman.</p>

[mark_denton1]

<p>Diffraction is always present; as soon as you begin to stop down the lens it increases. It therefore is a question of balancing your need for a smaller aperture (eg to increase DoF) with the increased diffraction of a smaller aperture. Only you can decide where this lies for a given image.<br>

How noticeable the diffraction is depends on your aperture and in particular the size of your print. The larger you print, the more noticeable it's likely to be.<br>

For me, I think the issue of diffraction is hugely overstated - what matters much more it me is the content and composition of the image and getting the right DoF for the shot. For me, these things almost always dictate the aperture I use, not worries about diffraction. IME most people aren't going to look at a Mam7 shot at f22 on a gallery wall and worry about loss of sharpness. You may have other priorities: only you can know this.</p>

<p>HTH</p>

[dave_s]

<p>What Mark said. There's another rule of thumb that some people here use. (I may be misquoting it.) If you divide 1700 by <em>n</em>, where <em>n</em> is the f-number, you get the maximum number of lines that can be resolved by a 'theoretical perfect' lens at that f-stop. This suggests diffraction will not be a limiting problem at f/16, at least for a 10x to 12x enlargement. But avoid f/32!</p>

<p>The pentagonal images of your aperture diaphragm are caused by flare. Shade your lens better if you can.</p>

[romain_j.]

<p>Thx for answers. The problem is that I need to expand to x30. That's why I wanted to know preciselythe degradation caused by F22. According to some advice found in other topic, F16 is quite correct / acceptable. Experiences?</p>

[mark_denton1]

<p>That's a huge enlargement. Assuming we're talking about single frames (rather than stitching), even a 4000dpi drum scan will only give you about 130ppi in printing. Grain will also be significant.</p>

<p>Is your subject flat or does it have significant depth? If the latter, everything I said about DoF still applies. The apparent DoF decreases as your print size goes up, so I'd suggest that this should still be your primary concern when choosing an aperture.</p>

<p>The only way to know for sure re diffraction is to make some tests. Shoot your subject at say f11-f22 and print 10x8 crops of an area of key detail in each frame at 30x enlargement and see what you find acceptable.</p>

<p>I've gotta ask out of curiosity: what are you shooting?</p>

[romain_j.]

 

 

 

 

 

 

I photograph actuality subject, especially outdoor shots. Social landscapes, action scenes, urban or natural landscapes, portraits, etc. ... but often quite large scenes that require a lot of sharpness and a lot of depth of field, for maximum detail. My subjects are often 10 meters is usually my distance. The shots need, I hope, X15 or X30 enlargements. Here is the problem. For you,Mark, more privileged the DOF than the diffraction? In fact, I can not estimate the actual loss due to diffraction. I did not realize, if it is really acceptable or not.<br /><br />For prints I intend to go through a good laboratory (I have my address), my problem is to do a very good shot at the time of shooting.

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[david_littleboy__tokyo__ja]

<p>I could not convince myself that I could see a difference between f/16 and f/22 on the Mamiya 7II with the 65/4.0 lens and Provia 100F, and I looked hard. Really hard. With a 60x microscope. Maybe if you were shooting Tech Pan or TMX100. Maybe.</p>

<p> </p>

[friedemann_pistorius]

<p>The difference between a handheld and a tripod based cable release shot will have much more impact on the sharpness of your image than the difference in diffraction between f16 and f22.</p>

<p>Also, the bigger the final print, the greater the viewing distance. People will not examine your images with a loupe, but will step back for a better view.</p>

<p>I'd suggest to make every effort to get sharp images: focus carefully, select the adequate f-stop for the desired depth of field, always shade your lens, use a tripod and a cable release whenever possible, scan and print your images with the best devices you can afford.</p>

<p>If all this doesn't lead to satisfaction, choose a bigger film format.</p>

<p> </p>

[romain_j.]

<p>Thank you for your answers. I usually work with the Portra 160 NC film, Manfrotto Tripod and cable release, and the Mamiya 80mm lens with its original a lens hood. I think its a good process to make powerfull shots for great enlargements.</p>