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11-12-2011, 12:40 PM   #2881
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QuoteOriginally posted by Makten Quote
I'm sure your lenses will perform better if you choose a larger aperture; say f/8 and thereabout. You'll have plenty of DOF in most cases of the above images anyway. I seldom use f/16-22 even when shooting 6x7.
Not with a 645D with these lenses. The DoF scale is already one stop narrower on the lens. For a given focal length, you have more DoF with a larger format.

11-12-2011, 01:10 PM   #2882
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QuoteOriginally posted by Yamanobori Quote
Not with a 645D with these lenses. The DoF scale is already one stop narrower on the lens. For a given focal length, you have more DoF with a larger format.
I know that very well, but f/16 is seldom necessary. The 645D has only a 1.27x (linearly) larger sensor than 24x36, which equates to an 1.27^2 = 1.6 stop difference in DOF. Not at a given focal length, but at a given angle of view. The difference between 645D and 6x7 is ~2.6 stops. Which means that f/22 on 6x7 gives the same DOF as 22/(1.4^2.6) = f/9 on the 645D.

Largest possible DOF might be a nice thing, but one should remember that most lenses give their highest contrast and sharpness at about 2 stops down from wide open. So the 120/4 Macro is probably much better at f/8 than at f/16. And then we haven't even considered diffraction, which can be an issue if you want to squeeze the best out of the fairly small 645D pixels.
You might as well get the same softness in the background from diffraction at f/16 that you would have gotten from limited DOF at f/8, while the subject in focus is just as smeared by diffraction as the background. I can't see how that would be a good thing.

So, don't stop down further than you have to!

Last edited by Makten; 11-12-2011 at 01:17 PM.
11-12-2011, 01:15 PM   #2883
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QuoteOriginally posted by Makten Quote
Itshimitis, not to underestimate your talent, but have you tried not stopping down so darn much? Even if diffraction is of little influence on these small images on the web, I'm sure your lenses will perform better if you choose a larger aperture; say f/8 and thereabout. You'll have plenty of DOF in most cases of the above images anyway. I seldom use f/16-22 even when shooting 6x7.

----------------------
I find that f/8 tends to throw too much out of focus. I am using f/11 more than f/16 now, and the 55-110 lens is sharper at f/11 as is the 33-55. I've printed these at 300 ppi on my printer and I see no effects of diffraction on them.

I am rather enjoying the 120 macro and it hasn't come off my 645D for a few days now!
11-12-2011, 06:37 PM   #2884
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QuoteOriginally posted by Makten Quote
I know that very well, but f/16 is seldom necessary. The 645D has only a 1.27x (linearly) larger sensor than 24x36, which equates to an 1.27^2 = 1.6 stop difference in DOF. Not at a given focal length, but at a given angle of view. The difference between 645D and 6x7 is ~2.6 stops. Which means that f/22 on 6x7 gives the same DOF as 22/(1.4^2.6) = f/9 on the 645D.

Largest possible DOF might be a nice thing, but one should remember that most lenses give their highest contrast and sharpness at about 2 stops down from wide open. So the 120/4 Macro is probably much better at f/8 than at f/16. And then we haven't even considered diffraction, which can be an issue if you want to squeeze the best out of the fairly small 645D pixels.
You might as well get the same softness in the background from diffraction at f/16 that you would have gotten from limited DOF at f/8, while the subject in focus is just as smeared by diffraction as the background. I can't see how that would be a good thing.

So, don't stop down further than you have to!
I shoot with a 645D and 120mm macro. You don't get much DoF at f/8. I can easily imagine that f/16 was required for Itshimitis and a 30" or 40" print will be beautiful from the images.

The problems of diffraction and CoC is related to chip/format size not pixel pitch--just as DoF and diffraction does not change with film of different resolving powers. Pixel peeping is never a real viewing condition. It is rather pointless to shoot for 100% screen resolution. You can easily shoot at f/16 on the 645D. And what would be the point at shooting at an aperture for technical perfection if there is not enough (or too much) DoF for the object? I almost agree with you, but stop down for what you need, even if it is wide open.

And you will not get the same softness in the background from diffraction at f/16 as you will at f/8--the background will be vastly sharper at f/16 with diffraction.

And this is not just from the numbers, which are right, but I have also made 40" test prints to see results. The effects of diffraction are vastly over stated.

11-12-2011, 06:39 PM   #2885
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QuoteOriginally posted by itshimitis Quote
I am rather enjoying the 120 macro and it hasn't come off my 645D for a few days now!
It is a very nice lens and I can see you are really enjoying it. I love the B&W Hofgarten image very much.

Don't ignore the 400mm, although it is not really an urban focal length. I hope to pick up a 300mm f/5.6 at the end of the week.

Looking forward to seeing more.
11-13-2011, 05:41 PM   #2886
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Left Heilbronn around lunch time to glorious sunshine that remained with us whe we got to Nuremberg.

Got to our hotel and my room has a balcony with a view to the castle which is a mile's walk away

Pentax 645D FA 400mm f/5.6 at f/13 and 1/250 ISO 320




I took a stroll up to the castle to grab some evening shots as and after the sun set:

Pentax 645D FA 33 - 55mm at 33mm and f/16 4 exposures




Nuremberg TV tower

Pentax 645D FA 400mm f/5.6 at f/8 and 1/25




A waning full moon on show so I grabbed my tripod and my 400mm lens

Pentax 645D FA 400mm at f/11 and 1/125 ISO 400



Last edited by itshimitis; 11-13-2011 at 05:51 PM.
11-13-2011, 08:13 PM   #2887
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Beautiful shot of the moon!

And one of mine:

11-14-2011, 05:58 AM   #2888
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Hello. My first post
Pentax 67 165/2.8



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Pentax 105/2.4 My wife



Pentax 67 panorama kit for 135mm film, lens 45mm. Lucky in rodinal.








11-14-2011, 01:19 PM   #2889
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645D + FA35mm
11-15-2011, 11:52 AM   #2890
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In Dresden at the moment, beautiful city. This is the Frauenkirche in the heart of the Altstadt

Pentax 645D FA 33 - 55 at 33mm and f/11 30 secs ISO 250


11-16-2011, 11:37 AM   #2891
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Dresden is an amazingly photogenic place. I could stay there for a week and still not get everything from it. With the Christmas markets on their way, what a wonderful place to visit...

This is the lion knocker on Dresden's castle. Last time I was here the door was shut, this time it was open which meant it was more side lit, so I dug out a little detail and then converted in Silver Efex

pentax 645D FA 120 f/4 macro at f/16 10 sec exposure ISO 100




I then walked down to the Augustus bridge and took this photo through the arches:

Pentax 645D FA 120 f/4 macro f/16 0.5 sec ISO 100




i returned later with my long lens to grab some mood with people in the shot. I had a lot of near misses with a nice shot of a couple but I was just too slow to catch it properly. I quite like this one although it isn't as sharp as I would like it. I like the feel of it though

Pentax 645D FA 400 f/5.6 at f/11 1/60 ISO 640 (taken from some considerable distance away)


11-16-2011, 01:32 PM   #2892
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Had another look at the last one and boosted the contrast and used the clarity slider a little


11-17-2011, 04:47 PM   #2893
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http://www.flickr.com/photos/32108329@N08/6355105271/in/photostream/lightbox/
6X7 and Super-Tak 2.4/105
11-18-2011, 03:54 AM - 1 Like   #2894
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couldn't sleep the other morning in Berlin, so grabbed my camera tripod and lenses and grabbed this shot by standing in the road at 0330 in the morning.

Pentax 645D FA 120 f/4 at f/16 3 images merged in photomatix using fusion




Last edited by itshimitis; 11-18-2011 at 04:03 AM.
11-18-2011, 05:54 AM   #2895
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Here's the Frauenkirche again in Dresden, adjusted contrast in Silver efex pro 2




For the benefit of Troy, here is the same shot in colour I have given it a similar contrast boost in LR3




I like them both personally....

Edit to add...

and with more contrast:


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