[pathdoc]

What are the down sides of using an APS-C lens on the K1?

1) In standard-ratio crop mode, you get a 15 megapixel APS-C image. The upside of this trimming is that there is no issue with vignetting, beyond what the lens would give on APS-C anyway.
2) In 1:1 crop mode (available with the latest firmware), you get approximately a 24MP image, IIRC. This does not always crop away ALL the vignetting for some of the wider fields of view.
3) For most if not all crop zoom lenses shot in full frame, there is either a very prominent lens-hood shadow or a very prominent outer dead-black zone at some or all focal lengths.
4) Similar problems exist for the very wide lenses (e.g. the super-compact but very nice DA15/4.0).

If you are the sort of person who shoots in raw and post-processes everything, you can selectively shoot in full frame, overriding crop mode, and cut away the shadow when you do the post work, thereby potentially gaining significant coverage over what auto-crop gives you. If you are planning to mount the image inside an odd-shaped (e.g. oval) frame, this may be of great advantage.

Some of the APS-C lenses, especially those based on earlier film designs, offer so little vignetting that at some distances and apertures it's practically unnoticeable; others are not so lucky.

Even with all this, however, there are a couple of things that need saying:

1) The in-body shake reduction function and image processing are significantly evolved from when (approx) 15MP was a Pentax APS-C standard (though the 16MP K-5 set standards in dynamic range which are still admired today).

2) All of the focus points are inside the APS-C zone, so you're not losing out on the use of any of them by shooting in crop mode.

[Craigbob]

1) In standard-ratio crop mode, you get a 15 megapixel APS-C image. The upside of this trimming is that there is no issue with vignetting, beyond what the lens would give on APS-C anyway.
2) In 1:1 crop mode (available with the latest firmware), you get approximately a 24MP image, IIRC. This does not always crop away ALL the vignetting for some of the wider fields of view.
3) For most if not all crop zoom lenses shot in full frame, there is either a very prominent lens-hood shadow or a very prominent outer dead-black zone at some or all focal lengths.
4) Similar problems exist for the very wide lenses (e.g. the super-compact but very nice DA15/4.0).

This is good to know. I've been looking at the DA 15/4 it looks like a sweet lens, but i'm bummed it's only crop format. On the K1 does it produce a 15 or 24 MP image? It's been so long since I've shot FF (back in my film days) that I don't know what 28mm would look like. I know standard is typically 35-50mm depending on who you talk to, but I've been shooting a lot with the canon 10-18 on my 70D and I love the wide field at 10mm. Hence why I'm looking at the Rokinon 14mm since the canon crop factor makes the 10-18 equivilent to 16-28. I wish I could afford the 15-30 but not right now. Do you know if they ever made such a lens for the film bodies? Did anyone?

If you are the sort of person who shoots in raw and post-processes everything, you can selectively shoot in full frame, overriding crop mode, and cut away the shadow when you do the post work, thereby potentially gaining significant coverage over what auto-crop gives you. If you are planning to mount the image inside an odd-shaped (e.g. oval) frame, this may be of great advantage.

I am one who shoots RAW and post processes their shots. Hell even my on my Cell phone (LG V10) I shoot RAW and process before posting anything. So this is nothing new to me. I've only recently begun printing anything out and that's only because I've entered some exhibitions.

Some of the APS-C lenses, especially those based on earlier film designs, offer so little vignetting that at some distances and apertures it's practically unnoticeable; others are not so lucky.

Even with all this, however, there are a couple of things that need saying:

1) The in-body shake reduction function and image processing are significantly evolved from when (approx) 15MP was a Pentax APS-C standard (though the 16MP K-5 set standards in dynamic range which are still admired today).

2) All of the focus points are inside the APS-C zone, so you're not losing out on the use of any of them by shooting in crop mode.

What APS-C lenses prodce less vignetting, this way I know what to look for.

Does having all teh focus points inside the APS-C zone cause any problems? Why are none of them outside the crop zone? I would think being so center focused on a FF camera would cause some missed shots where the focus point out sine the small zone.

Also does the K1 have Back Button Focus? I love that feature on my 70D.

[pathdoc]

IIRC the Canon crop factor is 1.6 as opposed to the Pentax/Nikon 1.5, so that might help you put things in the perspective of what you are used to.

[Tas]

What APS-C lenses prodce less vignetting

There's a whole thread on the topic right here mate: DA lenses on Full Frame: Test Shots thread - PentaxForums.com

[BullsOnParade81]

Yes it has back button focusing.

[Craigbob]

There's a whole thread on the topic right here mate: DA lenses on Full Frame: Test Shots thread - PentaxForums.com

Thanks, I've been keeping an eye on that one, but is seems like a lot of the shots/reviews are on APS-C cameras.

---------- Post added 03-23-17 at 04:40 PM ----------

Yes it has back button focusing.

Thanks. That's good to know.

[Tas]

Thanks, I've been keeping an eye on that one, but is seems like a lot of the shots/reviews are on APS-C cameras.

The thread is very old so the first 27 pages are a mix of Pentax APSC lenses tested on Pentax film cameras, Canon FF and I think some Sony FF mirrorless using adaptors. K-1 pics with DA lenses start on page 27 of the thread. You can also try here: PENTAX K-1 Laboratory | PENTAX K-1 Special site | RICOH IMAGING however some of the DA images will of course be shot in crop mode. You can also have a look for similar queries in the K-1 forum as it's been a fairly popular question that there's likely to be several threads on the topic. For example, there's a non Pentax camera part of the forum and there's probably a few samples in there too.

[clackers]

Thanks, I've been keeping an eye on that one, but is seems like a lot of the shots/reviews are on APS-C cameras.[.

?

Are any of them?

[Rondec]

This is good to know. I've been looking at the DA 15/4 it looks like a sweet lens, but i'm bummed it's only crop format. On the K1 does it produce a 15 or 24 MP image? It's been so long since I've shot FF (back in my film days) that I don't know what 28mm would look like. I know standard is typically 35-50mm depending on who you talk to, but I've been shooting a lot with the canon 10-18 on my 70D and I love the wide field at 10mm. Hence why I'm looking at the Rokinon 14mm since the canon crop factor makes the 10-18 equivilent to 16-28. I wish I could afford the 15-30 but not right now. Do you know if they ever made such a lens for the film bodies? Did anyone?



I am one who shoots RAW and post processes their shots. Hell even my on my Cell phone (LG V10) I shoot RAW and process before posting anything. So this is nothing new to me. I've only recently begun printing anything out and that's only because I've entered some exhibitions.



What APS-C lenses prodce less vignetting, this way I know what to look for.

Does having all teh focus points inside the APS-C zone cause any problems? Why are none of them outside the crop zone? I would think being so center focused on a FF camera would cause some missed shots where the focus point out sine the small zone.

Also does the K1 have Back Button Focus? I love that feature on my 70D.

I would look at the Irix 15mm or Samyang 14mm. Those are probably the best bang for your buck right now and honestly, for lenses this wide, auto focus isn't particularly important. Big thing with them is just to check for decentering. It's just pretty common in ultra wides like this.

Auto focus is decent on the K-1. I would just say that it isn't a sports camera and some folks struggle with tracking shots. Yes it does have back button auto focus.

Most of the DA limiteds except for the 15 and 21 are usable on full frame but have pretty dark corners, at least wide open. The DA zooms are pretty much crop only.

[interested_observer]

Most of the DA limiteds except for the 15 and 21 are usable on full frame but have pretty dark corners, at least wide open. The DA zooms are pretty much crop only.

As I understand it, you can pretty easily remove the rear light baffle from the DA 60-250 and it works well on the K1 full frame sensor. However, the 1.4xTC is only for ASP-C bodies (my current workaround to get to 300mm)

[Rondec]

As I understand it, you can pretty easily remove the rear light baffle from the DA 60-250 and it works well on the K1 full frame sensor. However, the 1.4xTC is only for ASP-C bodies (my current workaround to get to 300mm)

I think you are right. It does still take some modification to get you there and I wouldn't say as created right now that the 60-250 is full frame "out of the box."

[Craigbob]

I would look at the Irix 15mm or Samyang 14mm. Those are probably the best bang for your buck right now and honestly, for lenses this wide, auto focus isn't particularly important. Big thing with them is just to check for decentering. It's just pretty common in ultra wides like this.

Auto focus is decent on the K-1. I would just say that it isn't a sports camera and some folks struggle with tracking shots.

I'm gussing I'll go for the Samyang/Rokinon 14 then. The IRIX looks great, but at close to $1k in price is starting to get to close to the Pentax 15-30 price range.

[Rondec]

I'm gussing I'll go for the Samyang/Rokinon 14 then. The IRIX looks great, but at close to $1k in price is starting to get to close to the Pentax 15-30 price range.

I think the Irix 15mm firefly is just 400 dollars if you don't need the sealing. (IRIX 15mm f/2.4 Firefly Lens for Pentax K IL-15FF-PK B&H Photo) The Blackstone offers sealing and is 600 dollars on B and H.

[Craigbob]

I think the Irix 15mm firefly is just 400 dollars if you don't need the sealing. (IRIX 15mm f/2.4 Firefly Lens for Pentax K IL-15FF-PK B&H Photo) The Blackstone offers sealing and is 600 dollars on B and H.

Then I must have been thinking of the Laowa 12mm... Another nice lens it seems.

Between the firefly 15 and the Samyang/Rokinon 14 which is the better lens?

[Rondec]

Then I must have been thinking of the Laowa 12mm... Another nice lens it seems.

Between the firefly 15 and the Samyang/Rokinon 14 which is the better lens?

I think a lot depends on the copy. I have seen nice images from both (but own neither)

Pentax Irix lens club - Show us your photos... - PentaxForums.com

There is a Samyang lens club, but it is more of a grab bag with a lot of other shots from lenses thrown in for good measure.