[cowlitzJim]

After years of wondering, I shall wonder no longer. I picked up a used K-1 here and will soon be playing full-field 36×24!
Well, mostly - I do plan on using 24Mpx square mode quite a bit too.

Among my wonderings:

• How many of my DA wide lenses look amazing in square mode?
• How bulky is the K-1 when carrying only A28/A50/M85/M135?
• How good is my Quantaray pair (28-80 and 100-300 slowpoke) with 36×24?
• Ditto for my favorite old fave, the Rikenon 70-150/4?
• How wide is the DA21 field in square mode? I could calculate but that's cheating
• How's the 16-45 IQ >20mm in the short term, while I seek an x-wide prime?
• Will I keep the K-7, repair the Ks2, make the k100d a solenoid donor body for it?
• Do I need a new macro lens, or can I live happily with the DA35 Ltd?

No doubt a few other items will come to mind.

I'll enjoy having full-time Astrotracing w/o waiting for oGPS2, a twisted tilt screen, and numerous improvements from my K-5 era.
I may even get more serious about imaging with a more serious tool?

Thanks to all for accumulating so much data on DA lenses on 36×24 and how to make the most of the Pentax K-1.
My other camera is small as can be, a GX850 Lumix, a few little lenses.. and those Pentax primes.

---

Last edited by cowlitzJim; 12-09-2021 at 01:20 PM. Reason: adding to *list

[tncasual]

I can't really answer any of your questions, but welcome to Pentax Full Frame!

Have fun and share some images!

[cowlitzJim]

Thanks! I've watched for some of those answers, no doubt they are out there. Perhaps it's a sign this task is my own (or nobody cares boux-houx )

The camera is considered to be a gift from my parents; mom just moved up, two weeks short of birthday #99. Dad made it to 95 so they were very good for each other!
Their selfless efforts for their children won't make me wealthy but will put our finances in a better place.

[Paul the Sunman]

When I first bought the K1, I felt the overwhelming need for a (modern) UWA lens, something to match the DA 15 Limited on FF. Due to lack of options, I reluctantly settled on the DFA 15-30, which was wider than I needed (I thought) and heavier than I wanted. I am very glad I did.

However, if the DFA 21 f/2.4 Limited had been available then, I'm sure I would have gone that way instead.

Enjoy your explorations!

[Pentax Syntax]

Very few of the wide DA lenses work well even in square mode. The 12-24 is Ok from 20-24. The 14 DA shows vignetting even in square mode. DA 15 is also not great. The DA 40 and 70 work well in square mode.

Hope this is a help.

[Paul the Sunman]

Very few of the wide DA lenses work well even in square mode. The 12-24 is Ok from 20-24. The 14 DA shows vignetting even in square mode. DA 15 is also not great. The DA 40 and 70 work well in square mode.

Actually, the DA40 and DA70 work well in FF mode.

[C_Jones]

I use the Pentax 70-200 on my K-1 II. The results are excellent.

[Sakura]

With the A28/A50/M85/M135, it will be a good fit. All the "old glass" will work fine with the K1.

You especially will like the viewfinder of the K1 compared with the K7. I made the same step from K7 to K1-II. While using the K7 i was convinced my eyes were getting worse at a fast rate, i really wasn't able to manual focus anymore. (My first Pentax and the camera i was used was the MX)

When i got my K1-II, WOW, i wouldn't say it made me cry from happiness, but it wasn't far from that. Finally i could use manual focus again, it weren't my eyes getting bad, it was the much smaller field of view of the viewfinder.

The K1-II is a rather heavy camera to carry around all day, but man, what do i love that camera.

[JimJohnson]

At least the lower cost DA lens will range from slight to heavy vignette when used in FF mode. I personally find my DA 35 and DA 40XS usable in many situations. You'll just have to try and see if a lens is usable with your intended subject.
Here is what I have done...
I have three field bags, Super Program, K-3 and K-1.
I already had a couple DFA or FA, as well as KA lens that are mostly stored with my Super Program. That gave me a little time to selectively acquire three more lenses specifically for my K-1 field bag to cover the 20mm to 300mm range.

We will soon relocate to our winter home. This is small apartment size RV trailer with limited storage space. There is no room for all of the above (plus my medium format TLR kit). So I had to whittle things down. The K-3 & K-1 field bags were combined. I kept only one K-3 specific lens; the well regarded DA 18-135 - but had to use a body cap and store the K-3 and 18-135 unmounted.. I packed the Super Program kit into a quite small field bag. Pretty much all my K-1 lenses can be used on any of the three bodies. Other than my DFA 50 macro, I didn't pack any auto-focus primes.

For what it is worth, I use the Optech cross-body slings. I stripped this down to just my two-body sling to make things more packable. There were other gear choices to save space, but I think you get the idea.

[Bob 256]

After years of wondering, I shall wonder no longer. I picked up a used K-1 here and will soon be playing full-field 36×24!
Well, mostly - I do plan on using 24Mpx square mode quite a bit too.

Among my wonderings:

• How many of my DA wide lenses look amazing in square mode?
  All of them!
• How bulky is the K-1 when carrying only A28/A50/M85/M135?
  Oh Boy, will it impress everyone.
• How good is my Quantaray pair (28-80 and 100-300 slowpoke) with 36×24?
  Good enough.
• Ditto for my favorite old fave, the Rikenon 70-150/4?
  Even Better!!
• How wide is the DA21 field in square mode? I could calculate but that's cheating
  Won't let you go on this one - get out your slide ruler and start calculating.
• How's the 16-45 IQ >20mm in the short term, while I seek an x-wide prime?
  Still somewhere between good enough and even better.
• Will I keep the K-7, repair the Ks2, make the k100d a solenoid donor body for it?
  YOU WILL KEEP THE K-1!!!
• Do I need a new macro lens, or can I live happily with the DA35 Ltd?
  The K-1' bulk will scare your prey - go for a longer macro.

Just couldn't help myself. Welcome and I'm sure you'll find all the answers next year. A lot of those are subjective so one person's square mode is another person's dream. Enjoy your K-1!!!!!!!!!!!!

[UncleVanya]

I don’t own a k1. I own a Sony A7RIII and I have experimented with my Pentax lenses on it and the A7RII I had before it. The 12-24 is pretty good at 24mm, but I felt like 20-21 was about it. Some people claim 17-18mm I’m skeptical of the repeatability of that.

Pentax DA 12-24 @ 24mm by -vanya_42nd-

The reality is often stranger than you expect. The 10-17 @17mm is just as wide as it gets. In square crop you might squeeze a little more vertical info but at 10mm the view left to right is almost identical to what you get at 17mm due to the harsh vignetting. In essence the 10-17 is a 17mm “prime” on FF.

DA 10-17mm at 17mm by -vanya_42nd-

Pentax DA 10-17 at 10mm by -vanya_42nd-

Many DA primes longer than 21mm are quite reasonable in FF mode.

Da 40 - vignetting corrected in post:

Moist by -vanya_42nd-

HD DA 20-40 @30mm
Coverage by -vanya_42nd-

---------- Post added 12-09-21 at 04:53 PM ----------

Here’s a lowly sigma UC 28-70 f2.8-4. This image was cropped for content not due to coverage (lens is full frame) manual focus, cheap and still useable. Again on my Sony.

Yummy! by -vanya_42nd-

[pentaxus]

At least you have a plan. Wow.

[kiwi_jono]

I can't comment regarding DA 21 etc but I can say the A28 and A50 is pretty darn small on the K-1. In fact the FAs 28 - 77 are all relatively compact.
I know the square crop does work reasonably well with some of crop lenses (DA40 & DA70 are excellent in this regard). The DA15 not good though.

The K-5 -> K-1 is a huge step up (thats what I did over 3 years ago and I'm still loving it!).

[Joetitch]

LBA, resistance is futile 😀

[officiousbystander]

How bulky is the K-1 when carrying only A28/A50/M85/M135?

For a full frame the K1 is quite svelte. You might try and resist but you must get the FA 43 ltd.