[RICHARD L.]

I think you confuse "distorsion" (the curving of straight lines near the top or bottom of the image) with "field curvature" (plane of focus curved causing focus to be different in the center and in the corners of the image). No offense intended.

Regards

[diggles]

I think you confuse "distorsion" (the curving of straight lines near the top or bottom of the image) with "field curvature" (plane of focus curved causing focus to be different in the center and in the corners of the image). No offense intended.

Regards

Thank you for the clarification! Even though I've been doing this for a while I still get the terms mixed up…it seems there is a bit of both in the images I've uploaded, but I was trying to describe the distortion.

[672]

I kept the A over the FA originally (when D's were new) . The FA was more prone to flare and the A was slightly wider, as is your A , wider than your DFA. Can make a difference with interiors.......

Now I have the Z and 28-45 and 35DFA. 28-45 gets used a lot. DFA sort of a back up.

[SteveinSLC]

I have roughly the same setup. 645z, 28-45, and A 35. I kept the A 35 as it didn't cost too much, it's high quality, and pretty small compared to the 28-45. So it's a decent backup, or I can use it if I want something smaller.

[RICHARD L.]

I must admit I was tempted a lot by the D FA 35 mm f/3.5 HD. I saw a resolution test placing it at the apex of what a medium-format lens can deliver. But the 2000 $ (U.S.) price for a used copy on eBay kept me from purchasing it. The Canadian dollar exchange rate is around 0,70 $ (U.S.) so this lens would have cost me 2800 $ CDN, too much for the frequency at which I use this focal length. But when I saw an offer for an FA 33-55 mm f/4.5 AL at 400 $ (U.S.) on eBay from Japan, I thought "Let's give it a try". The lens reviews were quasi non-existent and the few available on the Pentax Forum were dismal, to say the least. So I ordered it and it was shipped from Japan to my home in "5 days" (via DHL), can you believe.

I was very apprehensive as everybody said corners were never sharp due to field curvature and this lens was a disaster. I tried it thoroughly and was always genuinely flabbergasted by the quality of the images it produced. I tested it mounted on a heavy tripod, at apertures varying from f/5.6 to f/32 and at 33 mm, 44 mm and 55 mm focal lengths. It is a "sweet lens", uniformly sharp, having great contrast, lovely colors and very high descriptive capability. Performance remains practically the same between f/11 and f/22, just the range I'm using in my landscape photography. Only thing to watch is pin source light intruding in the picture frame that may cause some flare.

So, to make a story short, I got for 400 $ a 33 mm FA lens that totally fills my needs.


Regards

"El cheapo"

[diggles]

I have roughly the same setup. 645z, 28-45, and A 35. I kept the A 35 as it didn't cost too much, it's high quality, and pretty small compared to the 28-45. So it's a decent backup, or I can use it if I want something smaller.

Since I mainly use my cameras for work, I like to have backups as well. I'll probably end out keeping them both 35s. My plan, as of now, is to use the HD D-FA on the Cambo Actus for architectural/interiors and use the A on the 645z for on location action shots. I really like the quality of the 28-45 as well, and the 28mm focal length, but it is a beast and doesn't seem to have a very big image circle at 28mm so I haven't had much luck with it when a shift is needed. The image circle does seem to get bigger and give more room for shifting in the mid range though.

Hey 672 - I also noticed right away that the A version of the lens is slightly wider, wasn't expecting that. That little bit of extra view could be just what you need when your back is against the wall.

Coming from FF 35mm, I'm so enamored with most all of the Pentax lenses I've tried on the 645z. Such a step up.

[Sandy Hancock]

The DFA is WR

No, it isn't. I have my copy on front of my while I type this. I don't know where you got that idea from. As far as I'm aware, the DFA/DA 25/4.0, DA 28~45/4.5, DFA 55/2.8 and DFA 90/2.8 macro are the only weather sealed 645 lenses.

The DFA645 35/3.5 a great lens though.

[barondla]

Since I mainly use my cameras for work, I like to have backups as well. I'll probably end out keeping them both 35s. My plan, as of now, is to use the HD D-FA on the Cambo Actus for architectural/interiors and use the A on the 645z for on location action shots. I really like the quality of the 28-45 as well, and the 28mm focal length, but it is a beast and doesn't seem to have a very big image circle at 28mm so I haven't had much luck with it when a shift is needed. The image circle does seem to get bigger and give more room for shifting in the mid range though.

Hey 672 - I also noticed right away that the A version of the lens is slightly wider, wasn't expecting that. That little bit of extra view could be just what you need when your back is against the wall.

Coming from FF 35mm, I'm so enamored with most all of the Pentax lenses I've tried on the 645z. Such a step up.

If you get a chance, please set up a tripod and photograph the same scene with both lenses to illustrate their slightly different fields of view.

Thanks,
barondla

[texandrews]

No, it isn't. I have my copy on front of my while I type this. I don't know where you got that idea from. As far as I'm aware, the DFA/DA 25/4.0, DA 28~45/4.5, DFA 55/2.8 and DFA 90/2.8 macro are the only weather sealed 645 lenses.

The DFA645 35/3.5 a great lens though.

Eeesh. Right you are, good catch.

[Sandy Hancock]

Eeesh. Right you are, good catch.

I wish it did have AW sealing - it's new enough to have HD coating, so I don't quite know why it missed out.

It would rarely come off my 645Z if it was sealed.

[672]

Barondla, the examples provided by diggles show the difference , check the links earlier in the thread

[diggles]

Barondla, the examples provided by diggles show the difference , check the links earlier in the thread

Thank you!

For those that are interested, I added small images and screenshots to the post so people can see the images without having to click the links. The links to the full-sized images and RAW files are still included. Also, the first test was taken on the 645z and the second test was originally taken on the Fuji GFX 50s with a Cambo Actus. This seemed to add extra variables so I retook the images for the second test using the 645z and edited the post accordingly. Hopefully the results will help.

[texandrews]

Thank you!

For those that are interested, I added small images and screenshots to the post so people can see the images without having to click the links. The links to the full-sized images and RAW files are still included. Also, the first test was taken on the 645z and the second test was originally taken on the Fuji GFX 50s with a Cambo Actus. This seemed to add extra variables so I retook the images for the second test using the 645z and edited the post accordingly. Hopefully the results will help.

How do you like working with the Actus? I had thought about them a lot in 2014 when I had my A7R, but was put off at the time by their lack of Pentax attachments. I could consider it again with my K1mkII, and I think the DFA 35 might work for me. I have some times when some movements could be handy---ran into one just yesterday. I have a Pentax K 28 shift for the KI, which is s decent optic and I have a 45 shift for my Z which is an Arsat lens, so a little iffy for what I do.

[diggles]

How do you like working with the Actus?

The Actus is a pleasure to work with. It is incredibly well made, not too big, and offers a lot of versatility. I'm using it with the Fuji GFX 50s. I'm not sure if the Actus will work with the K.

The difficulty for me has been finding the right lenses. Fortunately, Pentax 645 and 67 w/adapter lenses offer a wide variety of great choices. The 645 DFA 35mm, the 67 55mm latest and 75mm 2.8 are working very well for architectural photography…which is what I got the Actus for. I'm wanting to try out the 67 105mm f/2.4 as well.

What I like about using the Pentax lenses is that I can also use them on my 645z for handheld photography like environmental portraits. Focusing on the fly with an EVF is awkward to me. While the quality of the Fuji GFX is fantastic, it doesn't really feel like a camera to me. It feels more like a digital capturing device. When the Pentax 645z is in my hands, it definitely feels like a camera.

[RICHARD L.]

Hello, my friend,

When I got my 645 Auto Bellows, I noticed the auto-diaphragm of all 645 Pentax lenses remains open all the time, whether they are on the "A" position or set to a particular f/number. I realized I needed a cable release on the front standard of the Bellows to close down the diaphragm, otherwise all pictures would be taken wide-open. I had previously used my 645 FA 400 mm f/5.6 with my Pentax K1 body for fall pictures and I just now realized they were shot with the lens wide-open (they were not too bad in 24X36 format but could have been way better with the aperture closed to f/11 or f/16, had I been aware of this fact at the time). My question is : When using 645 lenses, how do you make sure your diaphragm closes to a middle aperture (let's say f/11) with your Actus which, I suspect, has no means to close down the 645 lenses apertures ? Pentax 67 lenses' diaphragms can be closed manually but not the 645s'. The 645 lens diaphragm has to be "actively" closed by the 645 camera body.


Regards