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09-26-2015, 11:11 PM   #181
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QuoteOriginally posted by MadMathMind Quote
Is this still the case for the FA31? I find its contrast to be quite excellent, certainly better than several other lenses I own.
The FA31 is a unique lens, it does indeed have higher than normal contrast among 28~35mm f/1.4~f/1.8 aperture lenses.I haven't experienced many focusing issues with the FA31 - at least not the same issues I have with the 18-35mm f/1.8 ART at 31mm.

QuoteOriginally posted by MadMathMind Quote
The FA77, however, often displays poorer contrast than the FA31, especially in bright light, probably because I use the built-in hood, which is likely not sufficient.
That is exactly the issue, the FA77 is based on an older full format lens design, the hood isn't suited for APS-C. The DA70mm f/2.4 has a hood that is better suited for APS-C. I just had a thought, has anyone who owns a DA70mm f/2.4 put the lens hood for it on an FA77 and compare it to the built in lens hood? they both have identical filter threads.


Last edited by Digitalis; 09-26-2015 at 11:17 PM.
09-26-2015, 11:48 PM   #182
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QuoteOriginally posted by Digitalis Quote
That is exactly the issue, the FA77 is based on an older full format lens design, the hood isn't suited for APS-C. The DA70mm f/2.4 has a hood that is better suited for APS-C. I just had a thought, has anyone who owns a DA70mm f/2.4 put the lens hood for it on an FA77 and compare it to the built in lens hood? they both have identical filter threads.
I may be able to do that in a few weeks - I do not currently own the FA77 but it is owned by a friend I will be visiting with the 11th of October.
10-16-2015, 03:13 AM   #183
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Now that I've had the lens for a while and shot quiet a a few weddings with it, here are my updated 2 cents.

For me, it's fine. Would I recommend it? It really depends on your needs.

I often use Liveview for stuff like group photos and even during some of the formal shots of the couple because of this lens - (my sample of) the lens seems to be good at low to mid range distances but the further away things get, the more it seems to want to back focus.

Hit ratio increased after I got the hub - but I still get many misses.

Being a f1.8 lens is super though, from the lowlight and also artistic shooting perspective. I also simply love how this lens renders. These two things are making me cope with the downfalls of the lens - if it hadn't been as good as it is, I would have had much harder time accepting the focus misses.

Then there is focusing speed. It's slow... it's reeeally slow.

If you can get a sample that just works, then I highly recommend this lens. If you find one that also has focusing issues, then I'd say you really need to know how you want to use the lens and whether you can accept the hit/miss ratio.
10-16-2015, 03:35 AM   #184
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QuoteOriginally posted by Zafar Iqbal Quote
you can get a sample that just works, then I highly recommend this lens. If you find one that also has focusing issues, then I'd say you really need to know how you want to use the lens and whether you can accept the hit/miss ratio.
Which is pretty much the same conclusion I came to with my review of this lens more than a year ago. This lens has AF issues, if you can work around them and be happy with the results: fine. If you can't deal with the AF accuracy issues, there really isn't much that can be done about it.

QuoteOriginally posted by Zafar Iqbal Quote
Then there is focusing speed. It's slow... it's reeeally slow.
Are you referring to AF in Live view? - all lenses are slow with CDAF on pentax DSLRs. PDAF is actually rather quick on my copy. At low light levels ( around EV 10) it is prone to hunting, especially around the 24~35mm FL range.


Last edited by Digitalis; 10-16-2015 at 03:53 AM.
10-16-2015, 05:46 AM   #185
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QuoteOriginally posted by Digitalis Quote
Are you referring to AF in Live view? - all lenses are slow with CDAF on pentax DSLRs. PDAF is actually rather quick on my copy. At low light levels ( around EV 10) it is prone to hunting, especially around the 24~35mm FL range.
No, I mean PDAF. For casual shooting it's OK but if I attempt to photograph people dancing, then the task becomes very difficult.
10-16-2015, 06:24 AM   #186
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Under that kind of scenario I would use the central AF point in AF-C mode. I hear that if you use the center AF point in SEL mode AF AC-C is somewhat more accurate than if it is in just the fixed center point AF mode. And this is all using the back AF button control.
10-16-2015, 07:11 AM   #187
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I might or might not have tried just that - but I don't remember it right now. I'll give it a try but I'm skeptical about it picking up that much speed.
10-16-2015, 07:33 AM   #188
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QuoteOriginally posted by Zafar Iqbal Quote
I'm skeptical about it picking up that much speed.
Fair enough, with the method I described AF speeds are similar to the FA31.

10-16-2015, 10:11 AM   #189
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QuoteOriginally posted by Digitalis Quote
That is exactly the issue, the FA77 is based on an older full format lens design, the hood isn't suited for APS-C. The DA70mm f/2.4 has a hood that is better suited for APS-C. I just had a thought, has anyone who owns a DA70mm f/2.4 put the lens hood for it on an FA77 and compare it to the built in lens hood? they both have identical filter threads.
Ok - both lenses are here. I have the two handy. First the dimensional info:
  • The DA 70 hood fits inside the FA 77 hood.
  • Retracted the DA 70 hood is about 1/8th of an inch longer than the FA 77 hood and at least 1/8th of an inch narrower in radius (1/4 inch overall diameter).
  • Extended the hood adds another 5/16th of an inch in length for a total increased length of about 1/2 an inch over the native FA 77 hood.

Here's a complete album with pictures of the lens and sky shots. I don't noticed any vignetting but I didn't have uniform skies and my eyes are not great at times for that type of comparison.
12-20-2015, 04:32 PM   #190
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I've about had it with this lens. I am strongly considering getting rid of it.

I recalibrated my FA31 and *now* I see what my camera is capable of. I never knew because I only had this lens and others that were either not sharp or with focus issues too. (Those have been calibrated out.)

Last edited by MadMathMind; 12-20-2015 at 04:45 PM.
12-20-2015, 05:55 PM   #191
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QuoteOriginally posted by MadMathMind Quote
I've about had it with this lens. I am strongly considering getting rid of it.
Yes, the FA31 will have that effect on owners of the Sigma 18-35mm f/1.8 ART.
12-20-2015, 07:13 PM - 1 Like   #192
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I've used mine quiet a bit at weddings and I'm starting to trust it more than I initially did.

The focusing is good at close proximity though it can fail - something like with 3-4 meters range, whereas at greater distances, it will fail more often than not. Fortunately, I do not need to be as quick to take photos when shooting over greater distances, so I manually focus using LV.

Overall, the lens performs much better than my Pentax 50mm f1.8, which is horrible no matter what distance.
12-21-2015, 05:26 AM   #193
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Some days ago, I attended a metal concert in one of the local clubs and it was the first time ever, that Sigma 18-35 and Pentax would refuse to focus at all, no matter what settings I used. I photographed multiple gigs in the club before, but apparently this time the light was way too dim. I did manage to make shots, but it is not quite clear, how much in focus they are, because only the silhouettes of artists were visible.
12-21-2015, 09:49 PM   #194
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QuoteOriginally posted by Zafar Iqbal Quote
I've used mine quiet a bit at weddings and I'm starting to trust it more than I initially did.
I've lost trust in it, for the most part. I don't carry it much anymore since it's so big and heavy. I use it only when I have to.

I'm willing to give it a shot after the FF comes out, see if that does better. I get it won't be making full use of the FF capability, but if it can produce nice landscapes, then I may consider keeping it, since the 27-52mm equivalent FoV is still pretty good. And I've got a lot of good filters for the lens...

QuoteQuote:
The focusing is good at close proximity though it can fail - something like with 3-4 meters range, whereas at greater distances, it will fail more often than not. Fortunately, I do not need to be as quick to take photos when shooting over greater distances, so I manually focus using LV.
And that's the rub. It makes it mostly useless as a landscape lens, where in this focal length is most useful, since infinity focus is...shaky, even at f/8 or f/6.3. I can get shots that look nice at screen size but pixel peep them and it's clear the focus is just off. I used to think it was limits of resolution of the camera, but the FA31 has showed me otherwise.


QuoteOriginally posted by Stagnant Quote
Some days ago, I attended a metal concert in one of the local clubs and it was the first time ever, that Sigma 18-35 and Pentax would refuse to focus at all, no matter what settings I used. I photographed multiple gigs in the club before, but apparently this time the light was way too dim. I did manage to make shots, but it is not quite clear, how much in focus they are, because only the silhouettes of artists were visible.
I've found that in low light, it's pretty much useless. It rarely focuses correctly.


I used to view this lens as a f/2.8 lens that sometimes worked below that. After reviewing a lot of my photos from the summer, I've come to view it more as a...f/8 lens? Not sure.
12-22-2015, 12:44 AM - 2 Likes   #195
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QuoteOriginally posted by MadMathMind Quote
I've found that in low light, it's pretty much useless. It rarely focuses correctly.
I shot many concerts with it, and the rate of misfocused shots was quite low. Some examples : https://flic.kr/s/aHskkqoAXH , https://flic.kr/s/aHskkq573K . You can look through my Flickr so check out other shots with this lens. For my copy F1.8 is perfectly usable in terms of focusing accuracy.
Here is a link to the flickr albums from the show where the combo refused to lock focus way too often : https://flic.kr/s/aHsko2sz1H .https://flic.kr/s/aHsko1CQd3 - different show, but same day. Here the combo focused rather well, I even tried AF-C and it worked.
So those claiming, that the lens in question is completely unreliable when it comes to focusing are either doing something wrong, or their copies are defective.

Last edited by Stagnant; 12-22-2015 at 01:41 PM.
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