[pres589]

Pentax isn't really hurting for good 35mm options in k-mount, though; the Sigma 35mm Art is still available new (I believe) and then there's the DA 35 2.8 Ltd, the discussed FA 35 f2's, the plastic semi-fantastic DA 35 f2.4 (it's sharp, colors are okay, some find it kind of boring in how it renders) and nearby are the FA 31 and DA 40's. I don't think we really would gain much by having that Tamron 35, as good as it is, given our existing options.

[ChristianRock]

I already have the 50mm1.4(great lens) and the DA 35mm f2.4(nice lens) but I want a full frame 35mm to use on my K1. Then I will save up and try to find a 20mm in great shape...

Thanks everyone for the information. I was wondering why it looked like the old was better than the new. But it makes sense that those are older reviews and there aren't nearly as many for the new HD model so that is the disparity. Appreciate your taking the time to answer! Peace

---------- Post added 10-14-2020 at 08:04 PM ----------

I just placed my order for the HD version. Should be here by next Tuesday. Hopefully, have some good weather next week and get some nice photos of the autumn leaves. They have really hit their peak this week. Thanks again everyone.

Congratulations on getting the HD 35 f2... but I wanted to say, the DA 35 2.4 you already have, covers the full frame as the optical design is actually based on the FA 35mm f2. You do have to manually change the K-1 to full frame mode in the menu, since the DA lens by default will cause the camera to select the APS-C crop. Have you tried that? Were you not satisfied by the results? I am curious...

[house]

Congratulations on getting the HD 35 f2... but I wanted to say, the DA 35 2.4 you already have, covers the full frame as the optical design is actually based on the FA 35mm f2. You do have to manually change the K-1 to full frame mode in the menu, since the DA lens by default will cause the camera to select the APS-C crop. Have you tried that? Were you not satisfied by the results? I am curious...

My copy of the FA35f2 and DA35f2.4 perform quite differently. The DA has quite a lot more vignetting and loss of sharpness towards the edges on FF. Strangely it also has different resolution characteristics the sharpness actually drops when stopping down from f2.4 and only recovers around f5.6 or so. The FA has the more traditional behaviour of improving continously when stopping down.

I don't like it when users here suggest various DA lenses are FF ready when both Pentax and Pentax forums have done tests showing that they aren't quite up to ff. It's being done all the time but in most cases you are better off sticking to apsc if you are using DA lenses. The weight and cost of K-1 isn't worth it imho if you use DA glass. The DA35f2.4 has smaller glass elements which show up in the above described vignetting and loss of resolution.

The DA35f2.4 is probably one of the better apsc lenses on full frame but it's not full frame compatible unless you limit your use of the lens to certain scenarios.

[ChristianRock]

My copy of the FA35f2 and DA35f2.4 perform quite differently. The DA has quite a lot more vignetting and loss of sharpness towards the edges on FF. Strangely it also has different resolution characteristics the sharpness actually drops when stopping down from f2.4 and only recovers around f5.6 or so. The FA has the more traditional behaviour of improving continously when stopping down.

I don't like it when users here suggest various DA lenses are FF ready when both Pentax and Pentax forums have done tests showing that they aren't quite up to ff. It's being done all the time but in most cases you are better off sticking to apsc if you are using DA lenses. The weight and cost of K-1 isn't worth it imho if you use DA glass. The DA35f2.4 has smaller glass elements which show up in the above described vignetting and loss of resolution.

The DA35f2.4 is probably one of the better apsc lenses on full frame but it's not full frame compatible unless you limit your use of the lens to certain scenarios.

I have never heard of a lens that loses resolution stopping down from wide open, then recovers at f5.6. I'd like to see some examples of that...

My use of the DA 35 2.4 on full frame is restricted to film, and on that it performs admirably. I can't really tell what aperture I'm using on my P30T though... since it has to be used in the A position. But I've read of others using it quite happily, especially on the Sony A7. I know some people use it on the K-1 as well but not as much. Maybe the 24MP sensor is a lot more forgiving than the 36MP K-1 sensor.

I always thought Ricoh/Pentax recommendation that these lenses (DA 35 2.4, DA 40 2.8, DA 70 2.4) be stopped down had more to do with vignetting. And compared to how those expensive Leica M lenses vignette, the Pentax lenses aren't bad at all...

[normhead]

I have never heard of a lens that loses resolution stopping down from wide open, then recovers at f5.6. I'd like to see some examples of that...

That's because it defies the laws of physics. I can't even think of a defect that would cause that.

[house]

I have never heard of a lens that loses resolution stopping down from wide open, then recovers at f5.6. I'd like to see some examples of that...

My use of the DA 35 2.4 on full frame is restricted to film, and on that it performs admirably. I can't really tell what aperture I'm using on my P30T though... since it has to be used in the A position. But I've read of others using it quite happily, especially on the Sony A7. I know some people use it on the K-1 as well but not as much. Maybe the 24MP sensor is a lot more forgiving than the 36MP K-1 sensor.

I always thought Ricoh/Pentax recommendation that these lenses (DA 35 2.4, DA 40 2.8, DA 70 2.4) be stopped down had more to do with vignetting. And compared to how those expensive Leica M lenses vignette, the Pentax lenses aren't bad at all...

I really loved the lens on apsc and center resolution continues to be great on FF. It's just a rather steep smear in the corners as the image circle doesn't quite cover FF. I made a lensfun lens profile for the DA on FF that removed the vignetting very successfully. You can't sort out the smeared edges though. The DA70ltd is very much the same but slightly worse than the DA35f2.4. I had hopes for both those lenses moving to FF but now only use them on apsc (which I only rarely use).

As you say many lenses particularly vintage and mirrorless ones vignette a lot and are sorted out by profiles. They tend to have a smoother vignette though not the sudden sharp drop you see with apsc lenses such as the ones you mention.

Here's a link to comparisons. Note the scale on the vignetting diagram
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/404546-hd-...ml#post4951339

[Spiritbro77]

It was my understanding from posts I read on here that it was hit and miss on a full frame. Sometimes it was fine and sometimes it had bad results. I like it fine on my K3. Very nice lens especially for the money. But I think I am going to be much happier with a full frame lens for the K1.

[mikesbike]

My copy of the FA35f2 and DA35f2.4 perform quite differently. The DA has quite a lot more vignetting and loss of sharpness towards the edges on FF. Strangely it also has different resolution characteristics the sharpness actually drops when stopping down from f2.4 and only recovers around f5.6 or so. The FA has the more traditional behaviour of improving continously when stopping down.

I don't like it when users here suggest various DA lenses are FF ready when both Pentax and Pentax forums have done tests showing that they aren't quite up to ff. It's being done all the time but in most cases you are better off sticking to apsc if you are using DA lenses. The weight and cost of K-1 isn't worth it imho if you use DA glass. The DA35f2.4 has smaller glass elements which show up in the above described vignetting and loss of resolution.

The DA35f2.4 is probably one of the better apsc lenses on full frame but it's not full frame compatible unless you limit your use of the lens to certain scenarios.

I don't doubt that your DA 35mm f/2.4 and FA 35mm f/2 perform differently, with the DA not as good on a FF DSLR body. In fact, OpticaLimits got different results between the two on APS-C, basically in favor of the FA. Although "based on" the formula of the older lens, the DA is obviously not exactly the same, as testing has shown as well. For one thing, the FA uses one aspherical element, while the DA uses one hybrid spherical element- maybe to save cost. There is also a larger available aperture for the FA- f/2 vs. DA f/2.4, enough to be meaningful. F/2.8 would be a full stop. And who knows if the elements are cut fully to FF size? But for a budget lens, the DA is amazing, and the FA is incredible especially on a FF body where it does provide a degree of wide angle, though not overly so, making it an ideal walk-around lightweight prime lens.

But this does not mean for a blanket avoidance of all designated DA lenses for FF use. Some of them have been direct design transfers from older models designed for 35mm film use, but with newer coatings and in a new lens body usually having WR and a silent lens AF motor. My DA* 200mm f2.8 is certainly one example. The DA* 300mm f/4 I believe is another. Pentax does have a list of DA lenses fully compatible with use on a FF body.

[house]

But this does not mean for a blanket avoidance of all designated DA lenses for FF use.

I agree, but I do think it would be more helpful to spell out that if you're buying a K-1 you will have to buy FF lenses to make use of the upgrade. DA's are only a good idea if you are happy to work within a rather complex network of parameters that differs for each DA lens. For practical photography this is quite limiting.

DA's are fine to tide you over whilst saving up or waiting for a bargain or when you know you will only use the lens in a specific way. The lens discussed here also seems to be one of the best ones. (from what I can gather)

I just find much of the DA on FF posting on PF a bit optimistic and not very helpful.