FA 31mm f/1.8 versus FA 35mm /f2 - That old debate again

Votesh · 11-26-2009, 10:49 PM

I've owned both, and prefer the 31mm. I never got too much use out of the 35mm. I just didn't like something about the pictures I got from it. Don't ask me what it was. For all I know, it was somehting to do with my skill, but I find it hard to ruin a picture with the 31mm.

I have little to no experience with the stuff you're looking to do with them, but the portraits I have taken with the 31mm are great. I find it's rendering to be along the lines of the FA* 85mm which is the best lens I've ever used for portraits.

**interested_observer** · 11-27-2009, 08:28 AM

The 31 came my way unexpected - and its my one and only fast fully automatic lens. Its a wonderful lens, however - for me, its expanding my skill set. I mainly do landscapes & cityscapes in the evening/night, so using the f1.8 aperature is very appealing. That said, the accompanying DoF issues are just the pure physics. I am very comfortable at the f8 range, however the sweet spot for this lens is at f4/5.6, so I am working my way up the to there.

The last set of images - actually a set of 8 stitched together into a panorama does have some issues (my skills - not the lens). I am up to f2.8 and I should just jump up to f5.6 and be done with it, so as to be able to get the DOF needed. Also, I am finding that with stitched images so wide, getting consistency across the entire sky color is difficult - especially under difficult lighting conditions.

Anyway, here is a panorama of 8 images all at f2.8, 0.4 sec, ISO 100 with the FA 31 and K20 on a tripod. All are untouched, just converted to jpgs for stitching.

I was going after the dark silhouetted hills against the iridescent blue sky at sunset. I was a bit too late to catch the band of yellow orange glow of the setting sun along the horizon. With the shallow DOF the focus across the depth of the image is not what I wanted - my skills and aperture selection - the lens locks and is wonderful.

The second one is my first attempt with the lens which is handheld using a K100, 4 images stitched f?? 1/8 sec, ISO 400 again with the FA 31.

By way of comparison the third image is using the 12-24 at 12mm, f8 at 6 seconds on a tripod and is a single image. The FA31 essentially takes the area just above Camelback mountain and expands it providing more detail. That is what caught my eye with the 31 in terms of the additional definition it provides - compared to the big all encompassing view from the 12-24.

gavinhw · 11-27-2009, 05:11 PM

I have the K10D and K20D bodies, and both the 31mm and the 35mm lenses. With the 31mm I had focus issues on both bodies (I had to dial in a negative value on the K20D's BF/FF adjustment screen).

On my K20D, the 35mm has a higher in-focus hit ratio.

If you can't adjust for BF/FF, I recommend the 35mm, unless you can critically test the 31mm on your body first.

And yes, wide-open, out-of-focus light sources are noticeably less circular (hexagonal) with the 35mm.

VAV · 11-27-2009, 05:35 PM

I too would be interested in seeing a comparison from a member who has both lenses... a while back on the 'other' forum, there was a long thread on the 31 vs 35 with sample images from both of the same scene... there was hardly any difference except for some slightly different bokeh.

Andi Lo · 11-27-2009, 08:13 PM

I do sometimes see the FA 35 images as being flat but I think that's just lens envy speaking. If one day I get the FA 31 maybe I'll let go of the 35, but for the time being its my small package one-lens-solution

axl · 11-28-2009, 02:45 AM

Originally posted by Andi Lo

I do sometimes see the FA 35 images as being flat but I think that's just lens envy speaking. If one day I get the FA 31 maybe I'll let go of the 35, but for the time being its my small package one-lens-solution

31 is definitely not small, so careful there.
Other than that there isn't much not to like on that lens

axl · 11-28-2009, 02:47 AM

Originally posted by gavinhw

I have the K10D and K20D bodies, and both the 31mm and the 35mm lenses. With the 31mm I had focus issues on both bodies (I had to dial in a negative value on the K20D's BF/FF adjustment screen).

On my K20D, the 35mm has a higher in-focus hit ratio.

If you can't adjust for BF/FF, I recommend the 35mm, unless you can critically test the 31mm on your body first.

And yes, wide-open, out-of-focus light sources are noticeably less circular (hexagonal) with the 35mm.

funny you mention the FF/BF. I had similar problem with 31. It's not a problem on GX20 and for K10D I got split image focusing screen to help when I want to use f1.8

BR
Peter

11-27-2009, 08:28 AM	#17
interested_observer Loyal Site Supporter Join Date: Jun 2009 Location: Tumbleweed, Arizona Photos: Gallery \| Albums Posts: 5,707	The 31 came my way unexpected - and its my one and only fast fully automatic lens. Its a wonderful lens, however - for me, its expanding my skill set. I mainly do landscapes & cityscapes in the evening/night, so using the f1.8 aperature is very appealing. That said, the accompanying DoF issues are just the pure physics. I am very comfortable at the f8 range, however the sweet spot for this lens is at f4/5.6, so I am working my way up the to there. The last set of images - actually a set of 8 stitched together into a panorama does have some issues (my skills - not the lens). I am up to f2.8 and I should just jump up to f5.6 and be done with it, so as to be able to get the DOF needed. Also, I am finding that with stitched images so wide, getting consistency across the entire sky color is difficult - especially under difficult lighting conditions. Anyway, here is a panorama of 8 images all at f2.8, 0.4 sec, ISO 100 with the FA 31 and K20 on a tripod. All are untouched, just converted to jpgs for stitching. I was going after the dark silhouetted hills against the iridescent blue sky at sunset. I was a bit too late to catch the band of yellow orange glow of the setting sun along the horizon. With the shallow DOF the focus across the depth of the image is not what I wanted - my skills and aperture selection - the lens locks and is wonderful. The second one is my first attempt with the lens which is handheld using a K100, 4 images stitched f?? 1/8 sec, ISO 400 again with the FA 31. By way of comparison the third image is using the 12-24 at 12mm, f8 at 6 seconds on a tripod and is a single image. The FA31 essentially takes the area just above Camelback mountain and expands it providing more detail. That is what caught my eye with the 31 in terms of the additional definition it provides - compared to the big all encompassing view from the 12-24. Attached Images Last edited by interested_observer; 11-27-2009 at 09:04 AM.

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11-26-2009, 10:49 PM	#16
Votesh Inactive Account Join Date: Apr 2008 Photos: Gallery Posts: 817	I've owned both, and prefer the 31mm. I never got too much use out of the 35mm. I just didn't like something about the pictures I got from it. Don't ask me what it was. For all I know, it was somehting to do with my skill, but I find it hard to ruin a picture with the 31mm. I have little to no experience with the stuff you're looking to do with them, but the portraits I have taken with the 31mm are great. I find it's rendering to be along the lines of the FA* 85mm which is the best lens I've ever used for portraits.

11-27-2009, 05:11 PM	#18
gavinhw Senior Member Join Date: Oct 2007 Posts: 145	I have the K10D and K20D bodies, and both the 31mm and the 35mm lenses. With the 31mm I had focus issues on both bodies (I had to dial in a negative value on the K20D's BF/FF adjustment screen). On my K20D, the 35mm has a higher in-focus hit ratio. If you can't adjust for BF/FF, I recommend the 35mm, unless you can critically test the 31mm on your body first. And yes, wide-open, out-of-focus light sources are noticeably less circular (hexagonal) with the 35mm.

11-27-2009, 05:35 PM	#19
VAV Senior Member Join Date: Jul 2007 Location: Hyderabad Posts: 160	I too would be interested in seeing a comparison from a member who has both lenses... a while back on the 'other' forum, there was a long thread on the 31 vs 35 with sample images from both of the same scene... there was hardly any difference except for some slightly different bokeh.

11-27-2009, 08:13 PM	#20
Andi Lo Veteran Member Join Date: Jul 2008 Location: Halifax, Nova Scotia Posts: 2,924	I do sometimes see the FA 35 images as being flat but I think that's just lens envy speaking. If one day I get the FA 31 maybe I'll let go of the 35, but for the time being its my small package one-lens-solution

11-28-2009, 02:45 AM	#21
axl Veteran Member Join Date: Mar 2007 Location: Nove Zamky, Slovakia Photos: Gallery \| Albums Posts: 7,183	Originally posted by Andi Lo I do sometimes see the FA 35 images as being flat but I think that's just lens envy speaking. If one day I get the FA 31 maybe I'll let go of the 35, but for the time being its my small package one-lens-solution 31 is definitely not small, so careful there. Other than that there isn't much not to like on that lens

11-28-2009, 02:47 AM	#22
axl Veteran Member Join Date: Mar 2007 Location: Nove Zamky, Slovakia Photos: Gallery \| Albums Posts: 7,183	Originally posted by gavinhw I have the K10D and K20D bodies, and both the 31mm and the 35mm lenses. With the 31mm I had focus issues on both bodies (I had to dial in a negative value on the K20D's BF/FF adjustment screen). On my K20D, the 35mm has a higher in-focus hit ratio. If you can't adjust for BF/FF, I recommend the 35mm, unless you can critically test the 31mm on your body first. And yes, wide-open, out-of-focus light sources are noticeably less circular (hexagonal) with the 35mm. funny you mention the FF/BF. I had similar problem with 31. It's not a problem on GX20 and for K10D I got split image focusing screen to help when I want to use f1.8 BR Peter

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