[xmeda]

You can also get 1.5x Kenko SHQ teleconverter (supports SDM/HSM too) and attach 12-24/4 to a K1 with it. You'll get full resolution and zero crop at the cost of some light and tiny bit of resolution with some lenses. Applicable to other APS-C-only lenses too.

[gatorguy]

You can also get 1.5x Kenko SHQ teleconverter (supports SDM/HSM too) and attach 12-24/4 to a K1 with it. You'll get full resolution and zero crop at the cost of some light and tiny bit of resolution with some lenses. Applicable to other APS-C-only lenses too.

I have three TC's and that's one of them. It's also the only one of the three I don't think I've ever used and I'm not sure why, tho probably because it doesn't autofocus like the other two so I don't think about it. I've even stacked my Pentax 1.7 and Tamron 1.4 together before on a *200 with satisfactory results. But never used the Kenko.

[gatorguy]

Were you using the 12-24 on K-1 as well (ff mode)?

I hear a lot of people feeling indifferent about the 31 between the two bodies. I think that's because it tips over into two different 'genres'. On FF the 31 is the beginnings of being a wild angle, the start of a landscape lens, but also still portrait, on crop it becomes a more straight up portrait lens. The 31 on the K-1 becomes a super duper 'environmental portrait' lens, something that gets you the person and where they are in one shot (street photography etc), on crop not quite so much but instead concentrates to being a classic portrait (effectively behaving like a 46.5/2.7 FF portrait lens).

I firmly believe much of the goodness in lenses actually is at the edges, and with FF glass on crop bodies you're missing that. Someone I know recently bought a DFA50 for their K-70. I find that a perplexing buy indeed. Why the DFA costs so much in the first place is that the edges of the lens are sharp, yet on a crop body yer basically throwing away $$ by never taking advantage of that (you never see the true edge). I mean ok, maybe that sounds harsh, I mean they still get a nice fifty, AW, Quick Shift, Silent AF, good AF etc, but still... one of the major optical benefits of the lens is a FF FoV with really good edge sharpness at wide open apertures.

When I've rented the K-1 it's been used with the FA77, Revuenon 50 1.4 and *200. I don't think I had the 31 then.

About that HD FA 50...
I don't think it was me because I don't recall mentioning it was on a K-70.
BUT....

It's an amazingly impressive lens on it. I have a LOT of really good glass, and the 50 may top them all. The sharpness, DoF, quick focus (nearly as quick at the 55-300PLM). the "pop" which is unlike any of my other lenses but perhaps closest to the Bower/Rokinon 85, and the color rendering are all standout features, quite unique from any of the other Pentax lenses I use.

Until you've tried it on your KP don't knock it.

[xmeda]

I have three TC's and that's one of them. It's also the only one of the three I don't think I've ever used and I'm not sure why, tho probably because it doesn't autofocus like the other two so I don't think about it. I've even stacked my Pentax 1.7 and Tamron 1.4 together before on a *200 with satisfactory results. But never used the Kenko.

That 1.4x Tamron should do the same job.

Pentax autofocus adaptor SMC F 1.7X AF TC can also be used for this task, but turns that DA12-24 into 21-40/6.8FF which is a bit worse than 18-36/6.. + you need to pre-focus a bit then.

I've used both kenko and F1.7xAF on my film MZ-10 with Sigma 8-16 for example. Nice wide results
Although tripod is needed then as I only have 100 or 200 sensitivity films

[BruceBanner]

When I've rented the K-1 it's been used with the FA77, Revuenon 50 1.4 and *200. I don't think I had the 31 then.

About that HD FA 50...
I don't think it was me because I don't recall mentioning it was on a K-70.
BUT....

It's an amazingly impressive lens on it. I have a LOT of really good glass, and the 50 may top them all. The sharpness, DoF, quick focus (nearly as quick at the 55-300PLM). the "pop" which is unlike any of my other lenses but perhaps closest to the Bower/Rokinon 85, and the color rendering are all standout features, quite unique from any of the other Pentax lenses I use.

Until you've tried it on your KP don't knock it.

All of what you have said is true it is an impressive lens. I'm just saying its slightly odd to use a lens on a crop body where the designers went full on hard core to give the lens on the platform it was intended (ff) to have edge sharpness. Funny to think on crop that you never take advantage of that 'hard to get' lens attribute, I can hear the designers crying in the corner

On crop the DFA50 is a 75/2.1, on FF it's a 50/1.4. One could argue a FA77 on the K-1 is a worthy comparison to a DFA50 on a crop, they would both be used for similar purposes sharing similar FoV and DoF.

I do love crop bodies, I don't want to be seen as a naysayer to crop. I just feel my experience to date (owning both FF and crop) is that FF lenses are better on FF bodies, because they were developed that way. However the opposite isn't actually true when it comes to crop lenses. If you can get away with using a crop lens on a FF body (in FF mode obviously) then it shines even more, at least this is what I have found with the HD DA 20-40 and DA 12-24. Of course some crop lens glass is not compatible, but... if you can get away with it, even at certain focal lengths, then it's definitely worth considering (just because a lot of the glass for K-1 is so damn expensive).

One thing I have noticed, people are not applying the 1.5x to the aperture enough when considering glass (and only applying 1.5 to the focal length for FoV FF equivalence). An HD DA 15/4 is really behaving like a 22.5/6 FF lens! Tell me when the last time you saw a FF prime lens selling with 22.5/6 traits? Even 22.5/4? Yes of course, the light coming in and exposure is the same as f4, but the DoF and how the image is presented is f6, that's pretty limiting in it's applications.
This is why I think when crop users whom do put fast glass (like 1.4) on their cameras they get ecstatically impressed because the 1.5x magnifier at these fast apertures doesn't affect massively so. 1.4 = 2.1, there is not a huge difference between those apertures, both 1.4 and 2.1 is well within bokeh dreamland
However, f2.8 is effectively f4.2, that's quite a bit different (imo), so all the f2.8 crop glass is rendering bokeh like a f4.2 FF lens. The HD DA 20-40 on crop is effectively a 30-60/4.2-6 lens, 60mm.. f6.... ouch, there goes a lot of bokeh. (and the aperture leaves f2.8 quite quickly on the 20-40, @24mm we're up to f3.5 already..

I even tested the HD DA 20-40 on my K-1 set to show this difference;

K-1 + HD DA 20-40 Crop Mode

23mm Crop mode, f2.8.
This is equivalent to 34.5mm in FF mode. f2.8 is behaving more like f4.2 here also.

K-1 + HD DA 20-40 FF Mode

36mm, FF mode, f4.
Similar to the crop mode but even though the aperture is more stopped down than the crop modes 23/2.8 version it's still a little more pronounced bokeh, perhaps accounting for the roughly 0.2 aperture difference. Exposure is also slightly darker.

Comparing the two, even though the camera stayed the same position each shot, framing almost exactly the same, I do much prefer the FF shot, the bokeh is more pleasing, better subject isolation, the exposure just needs lifted slightly perhaps It's not even a huge difference in aperture either, 0.2 difference? Clearly 'more stuff' is going on here but I think the point still stands.

And then of course using the same lens at 23/2.8 in FF mode on the K-1... well its doing something entirely different than the same lens on its rightful crop body home can never do. All ye bow and praise FF!

In summary, I'm not sure I'll ever buy a f2.8 or f4 lens for crop bodies ever again, its just too slow with not enough DoF variance for me to play with (thankfully the ones I do own play nicely with the K-1). Aiming for f1.2-1.9 glass for crop bodies is a good idea I think, it puts you in a place that is closer to what FF cameras and lenses are achieving and you can always stop down more if you want, the real point is you cannot make the lens faster than what it can do, but you can make it slower. FF gives additional advantage to this fact.

[gatorguy]

Bruce, take the same images with your K1 in crop and your KP. The two are not equivalent.

[pres589]

I don't do the crop factor times the aperture because *it doesn't make any sense*. Depth of field is near enough the same, aps-c vs ff, and you can prove that with your own photography by cropping a full frame image down to what the aps-c crop would perform. Or you can use online calculators to show the depth of field as affected by moving from full to crop image circles.


Meanwhile, imagine how killer it would have been for Pentax to create a 75mm f1.4 of the D-FA* 50's quality; you can see what that would be like by taking photos with that lens on a crop body. In line with that, the DA 15 was mentioned, and its f4 max aperture. Much like the M 20 f4, a lens I quite like. They're great optics and the f4 on crop or full frame doesn't change my opinion. Just bring a tripod if you think you'll run into a low light situation.

[BruceBanner]

Bruce, take the same images with your K1 in crop and your KP. The two are not equivalent.

They are roughly equivalent, lacking in megapixels obviously, but the points still stand because... physics. However I do take on board your point, which is why I hardly ever choose to use my K-1 in Crop mode when I have a 24mp KP right next to me, it's a just better overall result.

I just find it oddly perplexing that everyone is quite happily applying the 1.5x

I don't do the crop factor times the aperture because *it doesn't make any sense*. Depth of field is near enough the same, aps-c vs ff, and you can prove that with your own photography by cropping a full frame image down to what the aps-c crop would perform. Or you can use online calculators to show the depth of field as affected by moving from full to crop image circles.


Meanwhile, imagine how killer it would have been for Pentax to create a 75mm f1.4 of the D-FA* 50's quality; you can see what that would be like by taking photos with that lens on a crop body. In line with that, the DA 15 was mentioned, and its f4 max aperture. Much like the M 20 f4, a lens I quite like. They're great optics and the f4 on crop or full frame doesn't change my opinion. Just bring a tripod if you think you'll run into a low light situation.

Respectfully disagree.

It does make sense from an overall image perspective. It's ok to think;

'it's exposing like a f4 aperture, but presenting a DoF akin to what f6 looks like on FF, which happens to be the camera I use the most', it really just depends on your view point. If you think there is little to no difference between f4 and f6, or f2.8 and f4.2 then yes we will go round and round in circles. The point I made earlier is I think at the very wide apertures (f1.4-2) the differences are not as large as say f2.8-4.2 or f4-6.

The viewer of a photograph does not care about what available light you had to work with to begin with, it just cares about the large stuff first such as the content and whether the photograph sufficiently used focus in combination with aperture (DoF) to assist with the message/content. Some content is landscape, and the intent/message is to have the entire scene in focus from near to far. Some shots are environmental portrait, its about giving the primary focus to the person and secondary to the environment, some shots are all about the subject and we want very little context.

And no, that is not the same at all, that's an entirely different perspective and framing to the shot. If I then took my FF camera and moved to the same framing position as to what crop mode captures, but this time remain in FF and take the shot again... uhuh... exactly.

I'll try not to derail this thread any further from this topic matter. A more recent thread was started here (by me) and you're welcome to bump it with further questions or opinions;

Do we calculate Aperture to when using FF lenses on Crop Bodies? - PentaxForums.com

[beachgardener]

Sigma 35/1.4 Art

I wouldn't touch sigma with a forty foot barge pole. If you have the 31 that would be fantastic on the K-1 for groups and environmental portrait for sure

[BruceBanner]

I wouldn't touch sigma with a forty foot barge pole. If you have the 31 that would be fantastic on the K-1 for groups and environmental portrait for sure

Why's that then? I thought it had great reviews all round? The only thing that puts me off about it is the size of it.

Youtu.be

Youtu.be

[Ian Stuart Forsyth]

The 35 art is one of my favorite lenses for FF and landscape and for nightscape shooting

[beachgardener]

Why's that then?

not my cup of tea.

[BruceBanner]

Some more shots of the DA 12-24 on the K-1 in FF mode;

[BruceBanner]

[beachgardener]

Now that I like from the 12-24, a suitable use for it.