[Focusrite]

And some cropped shots of the 28mm and 45mm.

No CA correction has been applied to any of the shots, and the white balance is off between them. Please keep in mind that it was a very hot day, so any details of distant object would likely be partly spoiled by heat haze, and with a light breeze blowing there was some motion blur evident in some of the trees while shooting at 1/30 for the 45mm shots. However, with the corner crop of the 45mm, I see no reason to complain about sharpness in the corners, and the CAs seem to be much more manageable than at the wider end.

Attached Images

View Picture EXIF

File Date

 

View Picture EXIF

File Date

 

View Picture EXIF

File Date

 

View Picture EXIF

File Date

 

View Picture EXIF

File Date

 

View Picture EXIF

File Date

 

View Picture EXIF

File Date

 

View Picture EXIF

File Date

 

[Focusrite]

The knurled silver ring between the lens and camera body is the aperture control ring. There is no electrical contact between camera and body whatsoever.

[TDvN57]

Thank you very much for all this detail. Even though I like the 28-45 very much on the 645z, it looks like my hunch was right that it may not perform as well at FF. Soon after I bought the 28-45 I also picked up a 25mm DFA for that just in-case Pentax brings out a 645 FF version. When that time comes, I'll convert my 28-45 to a coffee mug and switch to the 25 DFA.

[Focusrite]

The 25mm holds a certain interest for me, however I have not found one inexpensive enough to tempt me to purchase and convert. I remember hunting around and finding an article or forum post somewhere from a chap who had tested the 25mm on film inside a glass-house of some sort, so lots of detail to check and lines to show any distortion. I suppose there is a difference between how detail is rendered on film, but I recall the results as also being satisfactory but not stellar at the edges? I might try to hunt for the article again.

I have mixed emotions about the 28-45mm on full frame 645. Mostly about the CA at the wide end. The vignetting was expected, but aside from the CAs the level of sharpness was better than I personally expected, considering its design case and that it's probably as good as or close to the widest native offerings for the Mamiya/Phase and Hasselblad H systems? I've heard mixed views about the Hassy 28, while the Mamiya/Phase 28mm is described as being "a good 31mm lens" due to poor corners.

I'm going to play around with it a bit more to come to a more rounded opinion, but I'm mostly just glad that the thing actually works.

As a coffee mug, it should have the volume to last all day

---------- Post added 12-26-21 at 05:26 PM ----------

Found the forum post via Google after trying a few different phrases. Looks like CA may also be a problem with it but at least the corners are bright.

My first shots with the Pentax 645 25mm f/4 - Page 2 - PentaxForums.com