Acquired a Pentax 645N, which lens should I get first?

Wolfram Malukker · Sep 14, 2024

As per the title-I have acquired a Pentax 645N, in good condition, with a single 120 insert. I intend to acquire at least one more insert and the plastic case that it will fit into. I have no lenses for this camera system yet. I don't absolutely need autofocus, but it's nice sometimes.

I'm thinking that the 80-160 OR the 40-80mm zoom first, which would let me figure out which focal length I am using the most. The 80-160 is also suspiciously cheap in many listings, so I wonder if it is just not that useful?

I am mostly looking at shooting landscapes and buildings, I don't usually do portrait style shots, but someday I might.

Will any Pentax-A lens fit, or do they need to be specifically Pentax-A 645 marked?

benveniste · Sep 15, 2024

Start with the easy one -- The lens should be explicitly badged for Pentax 645. "A" lenses are manual focus, "FA" lenses are autofocus.

I own the 33-55mm, 45-85mm, and 80-160mm FA zooms. The 80-160mm is better suited to "portrait-style" shots, especially for couples and small groups. For "landscapes and buildings," you may find that even the 45-85mm is a bit too narrow. It has roughly the same field of view as a 28-50mm lens for 35mm film. If you can find one, the 33-55mm is a good choice for landscapes and buildings.

All of the Pentax 645 zooms are "suspiciously cheap." In this era, you have to have a particular mindset to want to shoot medium format, especially film. IMO, that mindset and approach to the hobby lends itself better to prime lenses. The prices reflect that lack of demand more than any lack of performance or usefulness.

Wolfram Malukker · Sep 15, 2024

Right now, my most used lens on my 35mm cameras is the 35mm Super Takumar, which should be close to a 55mm lens on a 645? The two lenses I carry the most with my 35mm stuff are a 35mm and a 55mm.

Also could be that the 28mm I have is a bit too soft-focusing for my liking.

pentaxuser · Sep 15, 2024

What do you want as a first lens, wide angle, normal or telephoto?. My 654N came with an AF 75mm or normal focal length of 50mm if it were a 35mm camera. I have always found this one to be versatile enough and the AF is quite rapid for a Medium Format camera. Manual focus primes are fine, you just have to shoot scenes that lend themselves to being able to change lenses more often or use your legs to get the right distance so not a sports camera except for scenes where you can plan in advance for the action

pentaxuser

Wolfram Malukker · Sep 15, 2024

Well, I don't currently own any zoom lenses, they're all primes. I've also never had any autofocus capable cameras, this will be the first one for me other than a smartphone.

Like I said above-I normally pack a 35 and a 55 with me, I have a 135mm and 200mm but I've only used the 135mm a few times, so I stopped carrying it. There are a few times I'd have liked to have had it with me, but usually unless I know I'm going for a specific photo I leave it at home.

I think I'm going to find a 45mm or 55mm Pentax 645-A, and maybe look at finding a Pentax 67 105mm and the adapter. People seem to really like the 67's 105mm and the official adapters aren't too costly. Or, I could get the 45-85mm manual focus zoom for about the same cost as one 55mm prime.

Until I actually use the camera, it'll be hard for me to judge which lenses I'd be using the most.

OAPOli · Sep 15, 2024

The 75mm and 55mm lenses on 645 correspond to 43mm and 31mm lenses on 135 format, but cropped to 4:3.

pentaxuser · Sep 15, 2024

Well. Wolfram, it looks like you've answered your own questions in terms of what to do. It's always best that way

pentaxuser

MattKing · Sep 15, 2024

FWIW, I like using a 55mm lens as a "standard" lens on my Mamiya 645, and the 45mm lens provides enough of a difference to mean it is usually in the bag as well.
The two pair nicely with the 110mm lens.
The difference in aspect ratio between 6x4.5 and 135 film make a real difference in how I "connect" with different lenses. You will need to experiment with the camera to see if you experience something similar.

Wolfram Malukker · Sep 15, 2024

That's what I figured, Matt. I will pick up whichever of the 45, 55, 105, or 45-85mm zoom lenses I come across first at a price and condition that I like, and I'll start from there.

I'm really glad no one jumped in and said anything like "AVOID X LENS, it's terribad!" or similar-I went for the Pentax because of the quality experience I've had with my two 1960's era pentax lenses for 35mm. If they were that nice to use then, I would hope they're at least that good now!

DREW WILEY · Sep 15, 2024

With an adapter, you can also choose from Pentax 6x7 lenses. A little bulkier, but in certain focal lengths, even better, and sometimes better priced on the used market. The P67 75/4.5 is a superb optic, and especially well priced now; but it can be a bit dim for handheld focus, except at infinity; I recommend an accessory magnifier. The 105 is much brighter.

rduraoc · Sep 16, 2024

I recently got a Pentax 645N, but my main reason for getting it was to have AF - that narrowed my lens selection quickly. Also, the last time I had a zoom lens was in 2001 (in a Pentax Mz-50 that I had bought with savings from summer jobs). So, that also narrowed the choices dramatically. Another criteria for me was size, weight and portability, as this is my carry-on camera (I have a Fuji GX680III for when I feel the need to use a tripod...)

After that I was only divided between the FA 75 f/2.8 and the FA 45 f/2.8. Both had good reviews (in the very useful lens database of pentaxforums.com), but in the end I went for the 75mm because 1) its smaller and lighter and 2) it's the "standard" focal length and it suits my shooting needs. And so far I haven't felt the need to go wider, so it seems I made a good choice over the 45mm.

When GAS attacks again I may try the 67 lenses, with the adapter. There are no other FA lenses that spike my interest, and I believe the A lenses for the 67 are actually cheaper, and just as good as the 645 ones.

benveniste · Sep 17, 2024

rduraoc said:
When GAS attacks again I may try the 67 lenses, with the adapter. There are no other FA lenses that spike my interest, and I believe the A lenses for the 67 are actually cheaper, and just as good as the 645 ones.

I have a 300mm f/4 in Pentax 67 mount. It was cheaper than the 645 version, but lacks ED glass, so my guess is that it isn't "just as good." I do have the AB-82 screen and find it to be helpful with manual focus lenses.

I do admit I'm tempted by the 800mm f/4 that's currently offered on fleaBay for $2800, but I doubt I'd ever use it.

ant! · Sep 19, 2024

I have as well an 645n, and due to GAS a bunch of lenses. The most are rather cheap these days, especially the zooms. Things I want to add to whatever was said before:

a great source for the lenses is https://www.pentaxforums.com/lensreviews/SMC-Pentax-645-Medium-Format-Lenses-i4.html , there is also more about accessories
the zooms are long (weight is still alright), so handling and transport are a bit more challenging
most lenses are cheap, but I found the FA (autofocus) 75mm, 45mm and 150mm are quite a bit more expensive (plus the huge 600mm). For this reason, while I use for most others the FA version, for 75mm and 150mm I have "only" the manual A lenses. There is an, a bit difficult to find, viewfinder screen with split-screen, this makes manual focusing easier. I found one, otherwise you basically use the blank matte screen and the focus confirmation LED to focus, this works as well.
55mm, 135mm LS, 75mm LS (LS = leaf-shutter) and 600mm exist only in manual focus versions
ignore the D-FA and DA versions for the digital 645Z and 645D, these have no aperture ring and some don't cover the full format
I found most of my lenses in larger packages (4 lenses and more) from Yahoo Japan, like this I got them actually really cheap.
For landscape, you probably want the wider lenses, like the 35mm or 33-55mm, 45mm, 45-85mm, 55mm, 75mm, whatever you prefer. The 55mm or 75mm are very universal usable and compact. I like 150mm for portraits, wish I had the FA 150/2.8, but no complain about the A 150/3.5. The 150mm is still small-ish, from 200mm the lenses are quite a bit longer in format. Actually, if you like wide, a combination of 33-55mm + 75mm (+ maybe 150mm) would be a super flexible kit.
Some people in the Pentax reviews complain about the 45mm, I don't have it, so can't say, but it seems to get the lowest rating out of all (which doesn't mean it's actually bad, maybe just not as great as the others)
I had part of a lens pack actually an adapter for the 67 and a lens, but sold them. 67 lenses are larger/heavier, and of course no auto focus. Which doesn't mean you shouldn't use them...
Another adapter option would be to Pentacon 6 mount, you could use Zeiss Jena lenses like the Sonnar 180, Biometar 80 and 120, Flektogon 50...

rduraoc · Sep 20, 2024

Indeed @ant! , I had missed the Pentacon 6 lenses... what an incredible new world will be opening up there, when I look for a portrait lens (where AF will no longer be important...)

weasel · Sep 21, 2024

I have a Pentax 645 and two lenses, 55+150. Makes a nice walk around kit a slightly wide normal, and short tele

benveniste · Sep 21, 2024

rduraoc said:
Indeed @ant! , I had missed the Pentacon 6 lenses... what an incredible new world will be opening up there, when I look for a portrait lens (where AF will no longer be important...)

I tried two different Zeiss Jena lenses with my Pentax 645 -- a 180mm f/2.8 MC and a 300mm f/4 MC. In both cases, they arrived DOA due to aperture issues. So now I have a P6 adapter and no lenses which use it.

GRHazelton · Sep 21, 2024

I have a Pentax 645n and several lenses. The 35mm is truly excellent. It has barely perceptible distortion, considering its about like a 21mm on the 35mm format. Even Ken Rockwell agrees https://www.kenrockwell.com/pentax/645/645n.htm I also have the 55mm, the 75 mm normal lens and the 120mm which makes a good portrait lens in addition to continuous focusing down to 1 to 1. All are good. I also have the 200mm tele, which is fine

yurihuta · Sep 24, 2024

Wolfram Malukker said:
Will any Pentax-A lens fit, or do they need to be specifically Pentax-A 645 marked?

Any Pentax 645 A or FA lens will fit without an adapter.

As someone mentioned the DA and D-FA lenses will fit, but there is no aperture ring, so you are limited to either manual mode shooting wide open and Shutter priority I think (but quite limited) and no autofocus. The DA and D-FA were introduced after/with the 645D (digital version).

yurihuta · Sep 24, 2024

Wolfram Malukker said:
I'm thinking that the 80-160 OR the 40-80mm zoom first, which would let me figure out which focal length I am using the most. The 80-160 is also suspiciously cheap in many listings, so I wonder if it is just not that useful?

I am mostly looking at shooting landscapes and buildings, I don't usually do portrait style shots, but someday I might.

Either of these zooms are very good and that is reflected in the reviews on PentaxForums.

PentaxForums 645 lens reviews

The FA 35mm is stellar on film. Another data point for this lens is 16:9's review on film - scroll down to "Elegy or Eulogy?" for the 2007 piece.

16:9 Pentax FA 35mm review for film cameras

Wolfram Malukker · Oct 14, 2024

Just spent the last week shooting with this camera in Cape Canaveral.

The 45-85 zoom is the only lens I have and used, and I'm very pleased with the use and versatility-I did find that I was mostly using 75-85mm focal lengths, and I rarely was using the 45mm end of the dial. Tells me where I should look for lenses now!

Randy Stewart · Nov 17, 2024

Wolfram Malukker said:
I think I'm going to find a 45mm or 55mm Pentax 645-A, and maybe look at finding a Pentax 67 105mm and the adapter. People seem to really like the 67's 105mm and the official adapters aren't too costly. Or, I could get the 45-85mm manual focus zoom for about the same cost as one 55mm prime.

DO NOT buy a 105mm 2.4 lens for the Pentax 67 system plus adapter to use on your Pentax 645N. It would waste $700 you could use to buy several better lenses.
Reasons:
1. As a general rule, a lens designed for a 645 system is going to be sharper (and cheaper) than a similar lens designed to cover the larger 6x7cm format. Why pay more for less?
2. The 105mm 2.4 is not some mystical uber-lens of the sort praised in the social media myths. It was the first "normal" focal length lens designed for the 67 system, now nearly 60 years old. It was an okay lens in its day, but it within the Pentax 67 system, there are four lenses which might fill that normal lens role, and the 105mm is the optically least capable of them. Don't suck into all the internet bullshit which flows through YouTube. Basically, the P67 105mm 2.4 was designed as a marketing tool at the origin of that system. It fulled the role of "We got the fastest." at a time when "fastest" was a hot selling feature for camera lenses and in this case, a new MF camera system. Fastest meant some trade-off in "highest optical quality". Generally, it's like a "multi-tool". It does several things adequately, but nothing outstanding.

wiltw · Nov 17, 2024

Wolfram Malukker said:
Right now, my most used lens on my 35mm cameras is the 35mm Super Takumar, which should be close to a 55mm lens on a 645? The two lenses I carry the most with my 35mm stuff are a 35mm and a 55mm.

Also could be that the 28mm I have is a bit too soft-focusing for my liking.

35mm FL on 135 format is a 1.46x multiplier of the short dimension of the frame. So for 43mm short dimension of the frame on 645 format, the identical frame filling vertically is accomplished by 63mm! Shooting both cameras at 10' shooting distance with 35mm FL for 135 and 63mm FL for 645 captures a frame height of 6.7' for both.

The long dimension of the frame is harder to equate between the two formats, since the aspect ratio of 135 format is a bit 'overlong'...after all you have to trim off 6mm of the image from the 135 format frame to get the 24mm short dimension to fill a standard size of print paper (8x10)

Ben Hutcherson · Nov 17, 2024

Seeing this thread is timely for me, as I've just found myself the owner of a 645N. A local store talked me into a kit they had, with the 75mm and 45mm F-A lenses.

As much as I hate to admit it, the real selling point for me was the autofocus. I've compared it a lot to using a Nikon F4, both in the level of tech and in the speed/sureness of the autofocus. It's not replacing my Hasselblad, but I'd be lying if I didn't say that I've missed shots while I was cranking the focus ring all the way around on my Hassy lenses(almost everything I have is C, and buying just the 50/80/150 staples in CF, much less the rest of my kit, would cost more than I paid for this kit).

I've been eying the 200mm f/4 to add a longer lens as its on the affordable side.

With that said, for someone who also has a pretty decent Pentax 67 kit, including the 105 f/2.4 and a handful of other lenses, would a 67-645 adapter be a worthwhile addition? Ultimately I want to outfit this with FA lenses as much as possible, but seeing the current prices of the FA 150mm, and looking at my perfectly serviceable 165mm for the 67, for example, it's awfully tempting to spend ~$100 on the adapter...

kozesluk · Nov 17, 2024

If I was you (liking 35mm and 55mm on 135) I'd get F 55mm on 645 and then, maybe, FA 75mm.

99 % of my photography on 135 was with 35mm lens and I began even looking at something more 40-ish (38mm would probably be my ideal and I have liked Hi-Matic F for the FOV).
55mm on 645 is seems to me very similar to 35mm on 135 (compare the horizontal angle of view - 35mm lens on 36mm wide frame vs. 55mm lens on 56mm wide frame).

I have tested my Pentax-A 2.8/55 mm side by side to Zenzanon-PE 2.8/50 mm (and compared the Pentax-FA 2.8/75 with EII Zenzanon) and both the Pentax lenses to my surprise seem more even and sharper than the Bronicas.

Be mindful that although you can put Pentax-DFA 2.8/55 mm on the camera and it will work (and image quality should be superior) you can not use the camera in Aperture Priority modes as the lens doesn't have the aperture ring so you either end up with Shutter Priority or Auto modes when it comes to exposure. This for me really sucks and made me return the DFA lens even though I am not shooting anything besides landscapes. It just isn't a workflow I am able/willing to accept.

ant! · Nov 17, 2024

kozesluk said:
If I was you (liking 35mm and 55mm on 135) I'd get F 55mm on 645 and then, maybe, FA 75mm.

...

Be mindful that although you can put Pentax-DFA 2.8/55 mm on the camera and it will work (and image quality should be superior) you can not use the camera in Aperture Priority modes as the lens doesn't have the aperture ring so you either end up with Shutter Priority or Auto modes when it comes to exposure. This for me really sucks and made me return the DFA lens even though I am not shooting anything besides landscapes. It just isn't a workflow I am able/willing to accept.

In 55mm is unfortunately only the A (manual) and the DFA (no aperture ring), no FA (autofocus). I just use the A 55mm.

Acquired a Pentax 645N, which lens should I get first?

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