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f64
I have heard plenty of trash talk about the resolution of large camera lenses over the past few years. I have also heard that one should never close all the way down.
Well, I've just done the test for myself and I say its not true - at least for me - in the least. I pointed the camera out my front door and closed it down to f64. (I love depth of field.)
Now maybe some others want more sharpness than this example, but I am perfectly satisfied.... It's straight off the scanner, with no sharpening at all....
Saving for web made it way darker than I am going to print it, but take a look, and judge for yourself. I know I'm going to use f45 and f64 any time I want from now on, without fear that I'm losing something.
http://eigerstudios.com/sharpness64.html
Lenny
EigerStudios
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Re: f64
I stop way down always, rarely less than f45. I'll take the depth of field and image circle I get with my wide lenses at f64 any time.
Not sure what I may be missing out on, don't care.
www.timeandlight.com
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Re: f64
If I have to choose between areas out of focus or perhaps a slight loss of sharpness, I'll take the latter. And it is nice to use process that one can only contact print with.
When enlarging to 16x20 from 4x5, using f16 did get me sharper prints than negatives taken at f64 (Caltar II-N 150/5.6).
Vaughn
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Re: f64
It's simply a scientific FACT that diffraction affects sharpness at very small apertures. But everything obviously depends on the degree of print magnification
and everything else inbetween, and also on the precision of the film plane in the first place (ordinary filmholders don't hold film completely flat). In terms of personal technique, I generally stop down 4x5 lenses to f/22 to f/32 for the best combination of sharpness and depth of field, and 8x1O lenses from f/32 to f/64 - between these, it would be hard to note the difference in a 20X24 print, but distinctly noticeable in a 30X40 or 40X60 optical enlargement. Digital output is a little less fussy, since it can't resolve as much fine detail. Once again, I don't believe any of that "normal viewing
distance" bullshit - I'm referring to actual detail.
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Re: f64
Well, I just looked at your actual images, Lenny - the size of a postcard, and on the
web a ball of fuzz that could have been taken with a pocket point n' shoot with vaseline over the lens. Sorry to be sarcastic, but this kind of presentation proves zero with respect to either large format technique or the quality of current lenses.
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Re: f64
DOF is like taxes, you only stop down to obtain the required circle of confusion, and with taxes pay no more than necessary. With skill, you learn to maximize hyperfocal point, use movements carefully and therefore use f-stops < f64; and one finds legitimate ways to reduce their tax burden. There are times when f64, with all the skill you have, is still necessary. William Neill would commonly stop down to F64 and Dykinga would shoot at F45 and beyond with many challenging images where maximum DOF is required. In such cases, ultimate sharpness (visual acuity) is less important than obtaining the results you need. I find that using mild wide angles on 4x5 (75mm - 110)with a foreground object that is very close to the lens while trying to obtain focus on it and the distant landscape is the time employ beyond f45.
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Re: f64
Lenny,
I have done comparison shots of the same set up. I find that seeing the loss at really small apertures requires some high frequency data in the pictures. Blades of grass, really small branches, that sort of things. Without that, it is hard to see a difference. Without a direct comparison, it would be hard to see any difference at all, at least with very sharp lenses. I also use whatever is necessary for sharpness demanded by the composition. I am trying to use more limited DOF and stop worrying about about overall sharpness.
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Re: f64
I usually prefer overall focus with my LF images over maximum sharpness, and so I wouldn't hesitate to us f64 if needed. But I don't make very big prints. If you'd like to, you might want to check out focus stacking.
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Re: f64
A perfectly good eyeball can only resolve 5 lpmm at normal viewing distance.
So defraction kicks resolution from 50 lpmm to 20 lpmm,
so what, a 4x enlargement still looks tack sharp.
So with an 8x10, you can still make a very large print.
Bob
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Re: f64
I think it was Miss Manners who said something along the lines of: It's important to understand the rules so you can have fun breaking them.
In LF, I think it's important to understand how it all works, including diffraction. That way you can make intelligent and informed decisions during setup. It's all a tradeoff. Knowing what you are trading for what, and how much, can be the difference between good and excellent photographs.
That said, I often trade off some sharpness to get more DOF. And sometimes I'll accept more sharpness to get *less* DOF. It all depends on what I want to capture at the time.