[aslyfox]

you mentioned something in the 35 to 40mm range.

stretch it a little.

Grab the FA43.

Guaranteed will not go wrong.

The O P should be advised that obtaining a " Limited " either FA or DA series can be dangerous to the pocket book

It can be hard to stop with just one such lens

[garywakeling]

When the K1 arrives, just be happy in the knowledge that anything ever made by Pentax will fit, all the way back to the Asahiflex. Pixel peepers might complain about some perceived deficiency in rendering, or test charts and the like. However learning the unique characteristics of classic lenses can lead to a quite different joyful experience than clinical perfection, which by the way is available on most of the current HDA lenses if that is your desire.
One other question you asked was what current lens you might add to the K1, I would suggest the 28-105, a classic range and for the price, the quality of photos are impressive.
Some oldies





28-105





Enjoy your new camera and adventures

[Spock]

Vintage lenses can render beautiful images with a charm and character that may be missing in modern computer designed leases.
Sure, they flare more, often don't have sharp edges, and chromatic aberration and other flaws may be visible when 'pixel peeping' - but images don't have to be perfect to be interesting.

These were taken with a K10D and 1973 Takumar 85mm screw mount lens:


F1.8, 1/60s


100% crop:


F2.8, 1/50s


100% crop


F2.8, 1/50s

[MossyRocks]

Old lenses don't mean bad lenses. Here is an image I took in a fairly light polluted area but a darker portion of it (I was still in the core 7 count metro area of the Twin Cities). Granted the lens is an absolutly great lens but is an old manual focus lens (pentax A) and I was using it on my K-3 which is more pixel dense than a K-1. Point light sources are also extreamly punishing and will show all flaws with a lens.



Some of my favorite lenses are old and I do a lot of astrophotography with them. I like my old K-mount and M42 mount 50mm lenses, I recently got the K 35mm f/2 and I do like it a lot. I still even use my old M42 mount 200mm f/4 Takumar (S-M-C) all of which are good astro lenses. However for astro ultrawides didn't get good until recently.

[JimJohnson]

I agree with the many posters here. No matter how new or old, some lenses are umm, less desirable - they were on film also There are many good old lenses. If you dwell on a lens' weakness, you'll find it with a K-1. Every lens is a compromise, old or modern. Use a lens for what it does well and you'll be happy.

For what it is worth, I was checking IQ for long zooms on my K-1. They are notorious for lower contrast and slightly less sharp. My baseline lens was my KA SMC 70-210 f/4 - used at 210mm wide open. My test target was the shingles and lap siding on a church two blocks - roughly 200 meters away. I used the playback zoom feature to pixel peek. Several newer and reasonably rated lens at as close to the same settings I could manage, did not do as well as my older lens, even if I manually focused.

My Sigma APO DG 70-300 is almost as good and for both AF convenience and bit greater reach, is in my K-1's go bag. But I wouldn't hesitate to use older manual focus lens. Ditto for my KA 50 f/1.7 - if bokeh is important to me, I'll reach for it rather than my higher rated DFA 50 f/2.8 macro.

Best wishes on your lens choices!

[Papa_Joe]

I'am a happy owner of a K-1 since 6 weeks only. I have a lot of vintage pnetax lenses (M series mainly) I am looking forward to use. At the moment I'am testing my film area lenses for a walk around lens. What I can say until now about these is, that the Tamron 28-105 is workable but has it's flaws. Beside that, I'am sure, that what has already been said many times in the previous contributions by people with more experiences in full format, most my of my prime vintage lenses will give very nice pictures with the K-1. Even the Tamron does, under the right conditions.

What I like to add is, that you should not rule out to buy additonal high performing lenses, just because you are well stocked with legacy lenses. The K-1 will still perform better with these. I have until now short tested my Sigma 35/1.4 Art and my Sigma 70/2.8 EX DG macro on the K-1 and they give exceptional IQ on the K-1.

[John Shriver]

Focusing a manual focus lens with shallow DOF on the stock screen visually will be an exercise in frustration. For instance Pentax-A 50/1.2. The screen is too "bright" to do classic manual focus. You'll either need to use the AF focus assist or live view.

I had a nice Canon screen in my K-1 for a year. Made manual focus pleasant -- but totally flummoxed the metering system. So I went back to the stock screen, and replaced the A 200/2.8 with an FA.

[angerdan]

1. My question about the K1 is - does it reveal inherent weaknesses in classic lenses which a more modern (? matched) lens will not show ?
2. It would seem an odd decision to buy a FF camera if it was compromised by the use of much older lenses.
   In truth I'm not expecting that to be the case in most situations but am curious to know what others think - both classic lens fans and full on current generation lens shooters. Are for example late film era AF lenses a good option ?
3. A follow up - if I was to buy something similar to the Sigma above i.e. a general purpose lens with full integration into the K1 - what should I be looking at. I'm thinking of something around the 35-40mm mark and preferably not mega expensive. I also have a rangefinder habit......

1. With ★ Star-Lenses you won't see any weakness.
   PENTAX K-1 | Sample Photos for Pentax Cameras & Lenses - PentaxForums.com
2. All ★ Star-Lenses are perfect for the K-1!
   PENTAX K-1 Laboratory | PENTAX K-1 Special site | RICOH IMAGING
3. I'd recommend you the FA 43mm Limited. It's a Pancake
   smc: Full Frame Lenses between 31mm and 43mm with Auto Aperture, Autofocus | PentaxForums.com

Using MF lenses gives you three options for focusing (from analog to digital):

1. Exchangeable focusing screen with split screen indicator
2. Focus confirmation by AF sensor
3. Catch-in-Focus (same like above, but with automatic shutter release)
4. LiveView

[david94903]

I will take you up on that offer thanks nearer to when I make my final decision - much appreciated. And yes I have a "sweep bag" for my photo gear ! Fingers crossed.......

Great. Just let me know. I'm around for the most part.

[Spock]

For what it is worth, I was checking IQ for long zooms on my K-1. They are notorious for lower contrast and slightly less sharp. My baseline lens was my KA SMC 70-210 f/4 - used at 210mm wide open. My test target was the shingles and lap siding on a church two blocks - roughly 200 meters away. I used the playback zoom feature to pixel peek. Several newer and reasonably rated lens at as close to the same settings I could manage, did not do as well as my older lens, even if I manually focused.

I too have the A70-210F4 and it is an excellent lens. Out of curiosity, some years ago I tested it at 200 against a DA*200 F2.8 and FA*80-200 F2.8 and it didn't suffer by comparison, producing punchy, colourful and sharp images with good bokeh.

On the other hand, a newer but still old lens, the F80-200 F4.7-5.6 lacks contrast and sharpness compared to the aforementioned lenses but it's light weight and small size means it often has a place in my bag when I think I might need a longer lens on an outing.

[ZombieArmy]

Depends on the lenses. I think some old lenses resolve details just fine even under harsh APSC conditions.

Here's an example of the Pentax M 75-150 f4 at near 100% crop.


And some vintage lenses just have effects you can't really recreate in post, like the classic Auto Tak 35mm f2.3



In my opinion I think a lot of modern lenses far exceed specs that are even necessary in our daily photographic journey and there are lots of old gems to use. There are of course plenty of stinkers too but those are kinda obvious

[stevebrot]

I too have the A70-210F4 and it is an excellent lens.

Mine is always in the bag and in my opinion, its only weakness is purple fringing of specular highlights with digital.




Steve

[grey goat]

I recently got the K 35mm f/2 and I do like it a lot.

Yes. That's the first lens I thought of in the range you asked about, and I was glad to see MossyRocks mention it. It's sharp, and it renders nicely--wonderful bokeh, for sure.

I've got three modern lenses, DAs for my K-3ii and such, and another if I count the 40mm on my son's K-01. I probably have 20 older lenses. I don't have a K-1, so I can't say for sure how the K 35/2 would perform on it, but my guess is very well.

I don't have a problem with the newer lenses; it's just that the older lenses are more fun (I like manual focusing) and work very well for what I use them. I can't imagine your going wrong with any of the older lenses that get high ratings here on the site.

Anyway, the K 35mm f/2 is a keeper for me. Highly recommended.

[straton]

The only problem I have run into with film-era lenses on my K-1 is for lenses wider than about 30mm. The glass cover over the sensor (of which there was of course none in the film-era design process) creates a slightly longer optical path length at the edges than the center, noticeable in the images when the ray angles are wide-spread, as in a wide angle lens.. The strength of this effect seems randomly distributed over the lenses of this class.

Neither of the Pentax 24mm lenses I tested -- the SMC Pentax f/3.5 24mm nor the SMC Pentax f/2.8 24mm - came close to the sharpness of the Sigma 24mm f/2.8 Super Wide II Macro, particularly in the corners in portrait orientation. (In every lens mentioned herein, I found that shooting at f/11 avoided diffraction blurring, and gave better depth of field than wider apertures.). The Sigma 24mm f/2.8 Super Wide II Macro was excellent at f/11 from 10 feet to infinity. The SMC Pentax-A 28mm f/2.8, was likewise very sharp.

Since I’m getting older, I’ve been looking for zooms that I am willing to carry despite their being “less sharp in principle” than the five primes they replace, the full set of which I am not willing to carry anymore. A lens one has in hand always gives better images than the lenses one leaves at home.

I found that the Vivitar Series 1 24-70mm f 3.8-4.8 VMC Macro Focusing Zoom was sharper than three Pentax prime lenses, the SMC Pentax f/3.5 24mm, SMC Pentax f/2.8 24mm, and SMC Pentax f/2.8 30mm M lenses, almost as sharp as the Sigma 24mm f/2.8 Super Wide II Macro and the SMC Pentax -A 28mm f/2.8, and was much sharper than most zoom lenses of this class, particularly in the corners. Its one downside is that it is a push-pull zoom, which means that to keep the zoom from drifting, this motion is a bit stiff.

The Sigma Zoom-gamma II 21-35mm f/3.5-4.2 was slightly sharper than the Vivitar Series 1 24-70mm f 3.8-4.8.
The ProMaster Spectrum 7 19-35mm was sharper than Sigma Zoom in the center but worse in the corners, but is very much lighter and is auto focus for those who care.

For completeness, let me list the zoom lenses that I would not recommend, though the particular copy I tested might have been a bad outlier.

The following had some sharp focal lengths and some focal lengths that were very poor :
SMC PENTAX-FA 20-35mm F4 AL
Sigma UC 24-50mm not very sharp at 24 and sharp at 28
SMC Pentax 24-90mm F/3.5-4.5 SMC FA IF AL AF not sharp except at 28mm but less sharp than 28mm f2.8 Pentax-A
SMC PENTAX-F 24-50mm F4 less sharp than Sigma 24mm f/2.8 Super Wide II Macro
Tamron 24-48 Adaptall about as sharp as the Vivtar 24-70 much less sharp than the Sigma 24mm f/2.8 Super Wide II Macro

For these two the problem was in the focal range:
SMC Pentax-A 24-50mm f/4 not sharp at infinity but quite sharp from 3' out for a ways and pretty good at 1'
Sigma 24-60 sharper than primes at infinity but depth of field bad from 15 feet inward.

The following four were not sharp at all
SMC Pentax-M 24-35mm f/3.5
Tokina AF 20-35mm f/3.5-4.5 AF
VarioZenitar-K 25-45mm
Vivitar 19-35mm Series 1 A

Finally, on the very long end, on a tripod with the mirror locked up I found that the older, smaller, lighter Vivitar Series 1 100-500mm F/5.6-8 A zoom lens was sharper than the Sigma 170-500mm F/5.0-6.3 ASP APO in the foreground and as good at infinity.

Best wishes, Jack

[jrdimond]

You must have 645 glass. Get a k-mount adapter. All of mine are manual focus. These lenses were designed for manual focus and they feel just beautiful. With focus peaking and magnification, you can focus accurately on what you want. The lenses are cheap. Several are as good as modern glass, even in CA. No or very little light fall off. All of this because you are only using the center of the large image circle. I use them on my Sony a7r IV and they absolutely keep up with an even more demanding sensor than the K-1.

Of course, don't attempt to shoot a wedding this way, but for landscape, nature, macro and even some portraiture, I really enjoy using the best of 645 prime glass. Get a 300mm. Best long telephoto I have ever owned, even using a 1.4x and 2x.