K1 with Sigma DC 18-250 Macro HSM

Jodunca · 02-26-2017, 03:50 AM

I'm looking to upgrade from my K3-II and I would like to keep my DC 18-250 as a walking around lens.

Anyone tried one of these on the K1?

kooks · 02-26-2017, 04:16 AM

It will work.. using it at APC crop mode but not as a FF lens.

**Pentax Syntax** · 02-26-2017, 06:12 AM

I occasionally use my 18-250 Pentax DA on the K-1 in crop mode. You probably can get away with the 1:1 crop mode for a 24 Mp image using the Sigma. Be aware that through the viewfinder you will see a large vignetted image with a black box indicating crop mode. If you don't like this effect, you can use live view which works normally. Personally I am not a fan of crop mode as a general solution because of this effect which impacts composition in the viewfinder taking away one of the advantages of the DSLR.

dakight · 02-26-2017, 06:28 AM

I suppose it should go without saying, but one always has the option to shoot in full frame mode then crop in post. There is no reason at all to be bound by the built in crop ratios.

lennyl · 02-26-2017, 06:56 AM

K-1 + DA18-135WR

18mm,f11

135mm,f11

left - FF mode and manualy crop in editor
right - APS-C mode in K-1

funktionsfrei · 02-26-2017, 07:14 AM

The comparison between crop and crop seems to be somewhat ... futile.

More interesting would be a non-cropped FF image. Yes, that'll be with severe vignetting, but depending on the lens' construction and the focal length chosen, this could change, and there's even some chance for less vignetting with longer focal lenghts.

Could you post non-cropped FF images to compare them with APS-C crops?

lennyl · 02-26-2017, 11:48 AM

K1 + DA18-135WR

18mm f11 FF vs APS-C

135mm f11 FF vs APS-C

full size JPG
https://ulozto.sk/!ccrzkwq3vm9l/da18-135-k1-rar

funktionsfrei · 02-26-2017, 12:03 PM

You're aware that you can post images as part of this forum without using external file sharing services?

lennyl · 02-26-2017, 12:48 PM

if the AF focus is correct, details are the same, from FF mode and APS-C mode.

attachment JPG can be maximum 1400x900 pix

banep · 02-26-2017, 12:49 PM

If that was the question, Sigma DC lenses are not usable in full frame mode at any focal length and any apperture.
You'll have to use crop mode.

funktionsfrei · 02-26-2017, 01:01 PM

Originally posted by lennyl

attachment JPG can be maximum 1400x900 pix

Oh, that explains things. I might have been not to clear in my words. By "uncropped" I did not mean an image in the 100% camera resolution, but an image that shows the vignetting that you have removed, that is, the unuseable parts of the full frame image.

lennyl · 02-26-2017, 01:24 PM

if you want more examples, you can download full size JPGs from my previous post with FF mode vignetting and APS-C mode JPGs also.

i understand very well what you wrote. i want show the details in 1:1, thats all
for me is not APS-C/square mode solution, only a temporary solution who has not yet FF lenses

orignal APS-C lenses have brutal vignetting - for example DA15/4, DA18-135WR and others

funktionsfrei · 02-26-2017, 01:35 PM

Comparing a manual crop (done in post-processing from a full-frame shot) to an in-camera crop is quite pointless, since the result is invariably the same.

Why the bother?

normhead · 02-26-2017, 01:45 PM

The main thing is on the K-1, it's going to be a full frame equivalent of 12mm-175mm, even if you could use the full frame. With my 60-250 I can use it in FF mode, but it's distressing how much more field of view is involved if you're used to the crop FoV.

02-26-2017, 03:50 AM	#1
Jodunca New Member Join Date: Jan 2016 Posts: 1	K1 with Sigma DC 18-250 Macro HSM I'm looking to upgrade from my K3-II and I would like to keep my DC 18-250 as a walking around lens. Anyone tried one of these on the K1?

02-26-2017, 12:48 PM	#9
lennyl Forum Member Join Date: Mar 2013 Location: Slovakia Posts: 63	if the AF focus is correct, details are the same, from FF mode and APS-C mode. attachment JPG can be maximum 1400x900 pix Attached Images

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02-26-2017, 04:16 AM	#2
kooks Veteran Member Join Date: Apr 2011 Location: San José, Costa Rica Photos: Albums Posts: 794	It will work.. using it at APC crop mode but not as a FF lens.

02-26-2017, 06:12 AM	#3
Pentax Syntax Loyal Site Supporter Join Date: Feb 2010 Location: Maryland Posts: 595	I occasionally use my 18-250 Pentax DA on the K-1 in crop mode. You probably can get away with the 1:1 crop mode for a 24 Mp image using the Sigma. Be aware that through the viewfinder you will see a large vignetted image with a black box indicating crop mode. If you don't like this effect, you can use live view which works normally. Personally I am not a fan of crop mode as a general solution because of this effect which impacts composition in the viewfinder taking away one of the advantages of the DSLR.

02-26-2017, 06:28 AM	#4
dakight Veteran Member Join Date: Sep 2014 Location: Phoenix, AZ Photos: Albums Posts: 1,216	I suppose it should go without saying, but one always has the option to shoot in full frame mode then crop in post. There is no reason at all to be bound by the built in crop ratios.

02-26-2017, 06:56 AM	#5
lennyl Forum Member Join Date: Mar 2013 Location: Slovakia Posts: 63	K-1 + DA18-135WR 18mm,f11 135mm,f11 left - FF mode and manualy crop in editor right - APS-C mode in K-1

02-26-2017, 07:14 AM	#6
funktionsfrei Senior Member Join Date: Feb 2012 Posts: 183	The comparison between crop and crop seems to be somewhat ... futile. More interesting would be a non-cropped FF image. Yes, that'll be with severe vignetting, but depending on the lens' construction and the focal length chosen, this could change, and there's even some chance for less vignetting with longer focal lenghts. Could you post non-cropped FF images to compare them with APS-C crops?

02-26-2017, 11:48 AM	#7
lennyl Forum Member Join Date: Mar 2013 Location: Slovakia Posts: 63	K1 + DA18-135WR 18mm f11 FF vs APS-C 135mm f11 FF vs APS-C full size JPG https://ulozto.sk/!ccrzkwq3vm9l/da18-135-k1-rar

02-26-2017, 12:03 PM	#8
funktionsfrei Senior Member Join Date: Feb 2012 Posts: 183	You're aware that you can post images as part of this forum without using external file sharing services?

02-26-2017, 12:49 PM	#10
banep Banned Join Date: Mar 2013 Posts: 360	If that was the question, Sigma DC lenses are not usable in full frame mode at any focal length and any apperture. You'll have to use crop mode.

02-26-2017, 01:01 PM	#11
funktionsfrei Senior Member Join Date: Feb 2012 Posts: 183	Originally posted by lennyl attachment JPG can be maximum 1400x900 pix Oh, that explains things. I might have been not to clear in my words. By "uncropped" I did not mean an image in the 100% camera resolution, but an image that shows the vignetting that you have removed, that is, the unuseable parts of the full frame image.

02-26-2017, 01:24 PM	#12
lennyl Forum Member Join Date: Mar 2013 Location: Slovakia Posts: 63	if you want more examples, you can download full size JPGs from my previous post with FF mode vignetting and APS-C mode JPGs also. i understand very well what you wrote. i want show the details in 1:1, thats all for me is not APS-C/square mode solution, only a temporary solution who has not yet FF lenses orignal APS-C lenses have brutal vignetting - for example DA15/4, DA18-135WR and others

02-26-2017, 01:35 PM	#13
funktionsfrei Senior Member Join Date: Feb 2012 Posts: 183	Comparing a manual crop (done in post-processing from a full-frame shot) to an in-camera crop is quite pointless, since the result is invariably the same. Why the bother?

02-26-2017, 01:45 PM	#14
normhead Pentaxian Join Date: Jun 2007 Location: Near Algonquin Park Photos: Gallery \| Albums Posts: 40,451	The main thing is on the K-1, it's going to be a full frame equivalent of 12mm-175mm, even if you could use the full frame. With my 60-250 I can use it in FF mode, but it's distressing how much more field of view is involved if you're used to the crop FoV.