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Pentax 645 35mm lenses - comparison

rdeloe

Active member
This is just a quick pointer to a thread at the PentaxForums site for people who use Pentax 645 lenses and have been wondering how the modern D FA version does in comparison to the original manual A version. I know from previous threads in this forum that there are a few such people, especially among people who are looking for a wide angle shift lens.

In this post, a user who has both the A and DFA Pentax 645 35mm lenses posts samples, including RAW files, of test scenes made with both lenses. Based on my evaluation of those files, I'm not going to bother getting the newer D FA because the original A is excellent. (All the usual caveats apply about making decisions based on one copy of one lens and one test scene!) What this test does not do is speak to shift potential; the user who made the test is using a 645Z, so the whole image circle is not being used. Nonetheless, at the edges of the frame, the A is still better to my eye.

 
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Godfrey

Well-known member
I had a Pentax 645 kit (film only) and the Pentax-A 35mm lens. It is a terrific lens, crisp and sharp even wide open. No experience with the AF model at all for me...
 

scho

Well-known member
This is just a quick pointer to a thread at the PentaxForums site for people who use Pentax 645 lenses and have been wondering how the modern D FA version does in comparison to the original manual A version. I know from previous threads in this forum that there are a few such people, especially among people who are looking for a wide angle shift lens.

In this post, a user who has both the A and DFA Pentax 645 35mm lenses posts samples, including RAW files, of test scenes made with both lenses. Based on my evaluation of those files, I'm not going to bother getting the newer D FA because the original A is excellent. (All the usual caveats apply about making decisions based on one copy of one lens and one test scene!) What this test does not do is speak to shift potential; the user who made the test is using a 645Z, so the whole image circle is not being used. Nonetheless, at the edges of the frame, the A is still better to my eye.

I had both the original A version and the most recent D FA. Sold the latter with the 645z and kept the 35 A for use on my Cambo Actus. Still waiting for my HB 907x50c kit and will see how it performs with the 50 CII back on the Actus with the Pentax A-35. Works well with the Fuji 50R so I don't expect any problems with the HB 50CII.
 
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rdeloe

Active member
I had both the original A version and the most recent D FA. Sold the latter with the 645z and kept the 35 A for use on my Cambo Actus. Still waiting for my HB 607x50c kit and will see how it performs with the 50 CII back on the Actus with the Pentax A-35. Works well with the Fuji 50R so I don't expect any problems with the HB 50CII.
It's a really find performer on my GFX 50R as a tilt-shift lens. I use it with a Toyo VX23D. I'm curious to hear how it does on your HB 50CII, so if you remember a follow-up post on this thread would be welcome.

I was especially happy to discover that the D FA was not better because that saved me both money and time! What was striking to me in this person's files was that the A was clearly better than the D FA. That was a surprise. (Of course it could be copy variation, testing problems, etc. But he seemed careful so I'm fairly confident in his results.)

As a tilt lens the A is an interesting beast. It has close focusing elements that come into play around 1m. Beyond 1m I can focus it with the rail instead of the lens focusing ring. However, if I try that at < 1m, image quality in the corners is crap because the close focusing system is not used. But where things get really strange is tilt. When I use 35/3.5 for tilting, in most situations I now turn the lens to infinity on the ring, and focus with the rail; I actually have to move the standards closer than where they are when I set the lens up at its correct flange focal distance (something I can do with a VX23D but not a standard tilt-shift adapter). I can't explain how and why it's possible to get excellent focus and sharpness from top to bottom even though the close focus elements are not engaged... but it works so I don't complain.

Tilt example.jpg
 

rdeloe

Active member
Thanks for posting this. I'll be looking to add a few 645 lenses to my stable of MF glass.
I'm a fan of Pentax 645 lenses. I don't use them on my GFX 50R + VX23D outfit anymore because I have lenses that work better for that purpose (barring the SMC Pentax-A 35/3.5, which I do use). But when I'm using my 50R with just a tilt-shift adapter, I've come to really appreciate a few.
* The SMC Pentax-A 645 75/2.8 is a great choice -- small, light, sharp
* Surprisingly, the SMC Pentax-A 645 45-85/4.5 is outstanding from 45 to 75, and still really good from 75-85
Prices are great too considering what you're getting.
 

D&A

Active member
I don't have the link at the moment but when the original 645D was released, I tested multiple copies of most all the Pentax AF 645 lenses and wrote up my findings here on Getup. Since then I re-tested many on the 645Z and my original findings held up. I also tested copies (more than one) of the newer digital ready HD DA 28-45, HD D FA 90mm macro, DA & D FA 25mm f4 and some others and the new latest version of the HD D FA 35mm f3.5...and pitted that lens against the "A" version. Again these most recent tests on the 645Z which were not written up but mentioned occasionally in various posts here on Getup, appeared to show the HD D FA 35mm f3.5 lens had the edge in corner/edge sharpness over the"A" version (very close though) . Again sample variation may have played a role. The "A" version also showed more CA. With that said, the "A" version is most definitely a Best buy and a terrific performer. The HD D FA was exceptional too and was beyond head and shoulders over the original FA 35mm f3.5 which had very series issues with field curvature. All this is mentioned in my original large test of AF 645 lenses posted here on Getup. As an aside, how these 35mm lenses perform as a shift lens, I cannot say.

Dave (D&A)
 
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rdeloe

Active member
I don't have the link at the moment but when the original 645D was released, I tested multiple copies of most all the Pentax AF 645 lenses and wrote up my findings here on Getup. Since then I re-tested many on the 645Z and my original findings held up. I also tested copies (more than one) of the newer 28-45, 90mm macro and the new latest version of the HD D FA 35mm f3.5...and pitted that lens against the "A" version. Again these most recent tests on the 645Z which were not written up but mentioned occasionally in various posts here on Getup, appeared to show the HD D FA 35mm f3.5 lens had the edge in corner/edge sharpness over the"A" version. Again sample variation may have played a role. The "A" version also showed more CA. With that said, the "A" version is most definitely a Best buy and a terrific performer. The HD D FA was exceptional too and was beyond head and shoulders over the original FA 35mm f3.5 which had very series issues with field curvature. All this is mentioned in my original large test of AF 645 lenses posted here on Getup. As an aside, how these 35mm lenses perform as a shift lens, I cannot say.

Dave (D&A)
And what a great resource that work is Dave! I bookmarked it, so here's the link for everyone: https://www.getdpi.com/forum/index....ith-pentax-645-lenses-used-on-the-645d.35577/
 
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diforbes

Member
I'm a fan of Pentax 645 lenses. I don't use them on my GFX 50R + VX23D outfit anymore because I have lenses that work better for that purpose (barring the SMC Pentax-A 35/3.5, which I do use). But when I'm using my 50R with just a tilt-shift adapter, I've come to really appreciate a few.
* The SMC Pentax-A 645 75/2.8 is a great choice -- small, light, sharp
* Surprisingly, the SMC Pentax-A 645 45-85/4.5 is outstanding from 45 to 75, and still really good from 75-85
Prices are great too considering what you're getting.
Thanks for the recommendations!
 
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gurtch

Well-known member
I also saved that fabulous lens review, and it became my "Bible" when I had my 645D. I now have a GFX50R, and the older manual focus 120 macro is a real gem, and cheap on the used market. I use it with an adapter with built in tripod leg on the GfX 50R. I still also have MF Pentax 645 lenses in focal lengths 75, 150, 200, and 300mm with matching 1.4x extender, in addition to the 120 macro. I can vouch for the 35mm MF lens, it is excellant. I sold it as I have native Fuji lenses 23mm and 32-64mm. Dave (D&A) and I are long time "remote friends", he is a real gentleman.
Dave in NJ
 
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diforbes

Member
I also saved that fabulous lens review, and it became my "Bible" when I had my 645D. I now have a GFX50R, and the older manual focus 120 macro is a real gem, and cheap on the used market. I use it with an adapter with built in tripod leg on the GfX 50R. I still also have MF Pentax 645 lenses in focal lengths 75, 150, 200, and 300mm with matching 1.4x extender, in addition to the 120 macro. I can vouch for the 35mm MF lens, it is excellant. I sold it as I have native Fuji lenses 23mm and 32-64mm. Dave (D&A) and I are long time "remote friends", he is a real gentleman.
Dave in NJ
Hi Dave,
Which adapter are you using? I just got my 50r and want to try some Pentax MF lenses. Thanks!
 

rdeloe

Active member
If you're going to use Pentax 645 lenses on your GFX 50R, you could use a Fotodiox Pro P645 to GF adapter, which works just fine.

However, those P645 lenses have a large enough image circle to allow shift and tilt. For not a lot more money, consider a shift, or better a tilt-shift adapter. Even if you don't use the movements a lot, you'd have that tool at hand.

The only catch is that the standard Fotodiox Pro adapter has a built-in tripod food to which you can attach a mounting plate, while the Fotodiox Tilt-ROKR tilt-shift adapter does not. But that too is a solvable problem. I adapted an eBay special lens collar to fit around the front of my Fotodiox Tilt-ROKR; it works like a charm. Subsequently I discovered this thing, which looks to be a perfect fit: https://www.highpointscientific.com/zwo-78mm-holder-ring-for-asi-cooled-cameras-ringd-78

The price is right, and it looks very nicely made. Plus it should fit perfectly around the Tilt-ROKR. You will have to make a small modification to the Tilt-ROKR, but it's easy to do. If you're interested I can provide details.

The Kipon tilt-shift adapter for P645 to GF does have a tripod foot, but the adapter is much more expensive than the Fotodiox, and for tilt-shift it's actually not desirable to have a tripod foot because that locks you into one position. With a collar, you have much more flexibility and don't have to lay the camera sideways on your tripod head if you want to do a swing.
 

diforbes

Member
If you're going to use Pentax 645 lenses on your GFX 50R, you could use a Fotodiox Pro P645 to GF adapter, which works just fine.

However, those P645 lenses have a large enough image circle to allow shift and tilt. For not a lot more money, consider a shift, or better a tilt-shift adapter. Even if you don't use the movements a lot, you'd have that tool at hand.

The only catch is that the standard Fotodiox Pro adapter has a built-in tripod food to which you can attach a mounting plate, while the Fotodiox Tilt-ROKR tilt-shift adapter does not. But that too is a solvable problem. I adapted an eBay special lens collar to fit around the front of my Fotodiox Tilt-ROKR; it works like a charm. Subsequently I discovered this thing, which looks to be a perfect fit: https://www.highpointscientific.com/zwo-78mm-holder-ring-for-asi-cooled-cameras-ringd-78

The price is right, and it looks very nicely made. Plus it should fit perfectly around the Tilt-ROKR. You will have to make a small modification to the Tilt-ROKR, but it's easy to do. If you're interested I can provide details.

The Kipon tilt-shift adapter for P645 to GF does have a tripod foot, but the adapter is much more expensive than the Fotodiox, and for tilt-shift it's actually not desirable to have a tripod foot because that locks you into one position. With a collar, you have much more flexibility and don't have to lay the camera sideways on your tripod head if you want to do a swing.
Thanks for this!
 

gurtch

Well-known member
Hi Dave,
Which adapter are you using? I just got my 50r and want to try some Pentax MF lenses. Thanks!
I use the Fotodiox Pro PT645-GFX adapter. It looks to be well made. The first one I received was faulty, but the vendor promptly replaced it. It not only has a built in tripod foot, but it is an Arca Swiss type quick release, which all my cameras, tripods and monopods utilize. Very handy.
Dave
 

diforbes

Member
I use the Fotodiox Pro PT645-GFX adapter. It looks to be well made. The first one I received was faulty, but the vendor promptly replaced it. It not only has a built in tripod foot, but it is an Arca Swiss type quick release, which all my cameras, tripods and monopods utilize. Very handy.
Dave
Thanks. That's t the one I was considering. Fotodiox has been out of stock for some time; I have a stock alert in with them.
 
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