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Fun with the 645D

D&A

Well-known member
That's very kind of you Dave and would look forward to it...Pinot Grigio is just fine! The question is how much will my photography be improved after a glass or three :)

Dave with regards to AF fine tuning a lens with the 645D, sometimes it's made a small degree of difference while at other times it's been substantial. It greatly depends on not only on the particular focal length length or type of lens being used, but more often on how well (or not so well) the lens was calibrated when it left the Pentax factory during the film era days. Both variables are important.

For example, I was testing two samples of a 300 f5.6 lens on the 645D (after I posted my comprehensive lens testing) where one sample barely needed a +1 setting, while the other 300 f5.6 needed a +9 AF fine tune setting, just to get in the same ballpark in terms of performance as the 1st sample. These differences between the two lenses of course was most readily seen when identical files from both lenses were examined at 100% on the computer monitor.

Maybe what would be both fun and instructional to start with is to take for example your FA 400 5.6 set up on a tripod and focus on a stationary subject at mid-distance and take three shots. One with AF fine tuning set to -10, one shot with it set to zero and a third shot set to +10 and then go back and examine all three files at 100% (actual pixels) and determine if you observe any differences in terms of sharpness of the test subject you focused on.

Dave (D&A)
 

benroy

Subscriber Member
I've been reading your back and forths re: 645 lenses with great interest. I've been using the 55, 120 macro, 200/4 and 300/4 (645 > K adapter) with the 5IIs...results have been pleasing but great strain on focusing eye after cataract surgery. Will post examples if there is some interest.

Roy Benson

Roy Benson
 

gurtch

Well-known member
I've been reading your back and forths re: 645 lenses with great interest. I've been using the 55, 120 macro, 200/4 and 300/4 (645 > K adapter) with the 5IIs...results have been pleasing but great strain on focusing eye after cataract surgery. Will post examples if there is some interest.

Roy Benson

Roy Benson
Roy: I just had cataract surgery on my right eye a week ago (August 14). Even though I am right handed, I am left eyed. My left eye has a cataract, but not bad enough for surgery yet, so I am making out focusing with my dominant (left) eye. Good luck with your vision.
Dave in NJ
 

gurtch

Well-known member
Dave (D&A): do you fine tune with the lens wide open ( limiting depth of field) , or do you test stopped down to an aperature which you would be likely to use in the field? Thanks as always.
Dave in NJ
 

D&A

Well-known member
Dave (D&A): do you fine tune with the lens wide open ( limiting depth of field) , or do you test stopped down to an aperature which you would be likely to use in the field? Thanks as always.
Dave in NJ
Dave,

I too am right handed but left eye dominant and always focus with my left eye.

With regards to your question, I always first AF fine tune a lens wide open where the resulting depth of field is smallest. Sometimes after accomplishing this, I might repeat again but with the lens stopped down by a single f-stop. The reason being is that some lenses might have inherent softness when shot wide open and it's sometimes difficult to decern what and how much effect the AF fine tune is having.

Additonally although some might set the lens and focus on a subject at minimum focus distance, I have often found that sometime the greatest differences seen in Af fine tuning is at approx mid distance range. Let us know how it goes Dave. Thanks!

Dave (D&A)
 

tsjanik

Well-known member
Hello

I am a hobbyist and recently acquired a pre-owned Pentax 645D. Previously I used D700/D800 with Zeiss and Leica-R lenses. I wanted to try out the medium format and hence made the switch. A couple of shots...
Welcome. Nice to see this thread revived! Here are some shots taken yesterday which may be of interest to Pentax users. I used the 645 600mm A* lens with a 645D and K-5 (via adapter). The shots are of waterfowl in a local harbor (mostly red-headed ducks). The camera positions were the same in both cases. The 645D shot is cropped to give duck sizes approximately the same as in the uncropped K-5 shot. Opened with ACR and no adjustments to either other than exposure. I'm quite surprised at the difference in color (AWB for both cameras). CCD vs. CMOS?

Tom
 

Shashin

Well-known member
Tom, there seems to be speculation that manufacturers weaken the Bayer filters on the sensor to improve noise and high ISO. That with different color processing and interpolation could give that result. BTW, were the temperature and tint values the same in ACR? If not, I would make those the same and then see the difference. Sensels, whether on a CCD or CMOS, are color blind.

I really like the color in the 645D. Color is one thing Kodak did very well.
 

Shashin

Well-known member
Welcome Jamgolf. You will find most Pentax 645D shooters posting in the medium format section of the forum in the Fun with MF thread. If you find this thread lonely, please go there.
 

tsjanik

Well-known member
Tom, there seems to be speculation that manufacturers weaken the Bayer filters on the sensor to improve noise and high ISO. That with different color processing and interpolation could give that result. BTW, were the temperature and tint values the same in ACR? If not, I would make those the same and then see the difference. Sensels, whether on a CCD or CMOS, are color blind.

I really like the color in the 645D. Color is one thing Kodak did very well.
Will, I adjusted nothing except exposure in ACR; the temp and tint values are 0 and white balance "as shot". I can process the K5 to look like the 645D, but the 645D file is much better out of the camera.

Tom
 

Jamgolf

Member
Welcome Jamgolf. You will find most Pentax 645D shooters posting in the medium format section of the forum in the Fun with MF thread. If you find this thread lonely, please go there.
Thanks for the welcome & likes. I appreciate it.
I'll check out the other thread as well.

Cheers!
 

D&A

Well-known member
Welcome Jamgolf and enjoy your 645D!

Tom even looking at these web resolution images, I can plainly see the superiority of the 645D and not just in color/tonality but that certainly is its strong suit. Whether its CCD vs. CMOS I honestly can't say but images right out of the 645D never fails to impress me. This is much akin to images coming right out of the M9. I cannot say this about most other digital cameras I use. Both CCD of course so I'll let others come to their own conclusions.

Dave (D&A)
 

D&A

Well-known member
Nice Tom! I've always been interested in the architecture of I.M. Pei . As for the 45-85 645 zoom, it too never ceases to amaze me with it's excellent performance, even though it's a tiny bit weaker on the long end. Think how relatively little this zoom can be had for compared to newly released Pentax 645 lenses. All one has to do on a damp rainy day is throw over it a plastic bag or two and you even turn it into a weather resistant lenses...LOL!

Dave (D&A)
 

Dogs857

New member
I know that this is an old thread and that most people post in the "fun with MF" thread now.

I also know that this was most helpful when I was researching my new camera choice and I would like to contribute to it.

Thursday Island
Pentax 645D - 55mm AW
CPL + 10 stop ND

 
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