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Laurentiu Cristofor · 11-21-2010, 12:55 AM

AF happens with the lens wide open. So it doesn't matter whether you can see the DOF changes or not as you stop down. DOF is thinnest at 1.4 - if the AF system can focus there, that will work for 2.8 too. Of course, this doesn't take into account focus shift - that's the problem you've been exploring in this thread and one that AF systems don't seem to compensate for. That happens because AF determines focus at 1.4 and then stops down to 2.8, but at that aperture, the focusing is incorrect, so you'll get back focus or front focus. With the proper lens-camera interface, the lens manufacturer could encode the focus adjustment for a lens with focus shift, but it doesn't sound like this thing is done currently.

Rin · 11-22-2010, 12:52 PM

Are the current variations of the Sigma 50mm 1,4 without issues or is front and back focus still very common.

SPA · 11-22-2010, 02:47 PM

Check FW version. I have similar problem with my 35/2.8 Macro. But with last two version of firmware, the AF is more stable.

edit: I just saw that you use last FW. You can try set it again. Some time helps.

Rin · 11-23-2010, 11:27 AM

tomorrow i will receive the same lens and a K5, i wonder how it will eprform i can return it within 2 weeks anyway

philippe · 11-24-2010, 06:27 AM

I have an other issue with my Sigmalux I didn't mention before. In LR3.3 this lens is 'recognized' as a 70-200 mm F2.8 EX DG Macro HSM II zoom

. So the Lens Profile corrections are done for the wrong lens AND as mounted on a Nikon camera, go figure, a Nikon

! That 'Nikon thing' is indeed a very strange turn of events

!

**Digitalis** · 11-24-2010, 06:32 AM

I had some focusing issues with my sigma 100-300mm f/4 I adjusted it but it would still drift in and out from week to week. In the end I just gave up and reset it to +1 and strangely it seems to have settled down.

I'll also mention that my sigma 100-300mm f/4 is also recognised by light room as a sigma 70-200mm f/2.8 - which is very annoying when I want to do lens based image searches.

knock on wood.

icypepsi · 11-24-2010, 10:48 PM

Originally posted by Rin

Are the current variations of the Sigma 50mm 1,4 without issues or is front and back focus still very common.

Sorry, I've been a bit busy. Well, the issue is definitely there. But not just with Sigma. I think it is "noticable" with lenses wider than F2.8. Congratulations. So, how's your K5 + Sigma turning out?

As for me, I would settle with that problem, coz there's no cure as of today. Like an online article pointed out, getting used to the lens' behavior, manually! I hate it, but I really really love the way a prime's picture's look. That "raw" brightness and sharpness.

For myself, I also discovered that 50mm was a bit short for my style of shooting. So I'm actually waiting for the Sigma 85mm F1.4 HSM. They seem to have solve this "focus plane shift" problem; of some online posts I read. They are on sale right now, but I just don't have the time to buy one and test... So, for me it's going to be this new year. Money's intact for it!
I'm also considering the FA 77mm F1.8. Seems more sharper, with screw-drive AF.

Last edited by icypepsi; 11-24-2010 at 11:03 PM.

icypepsi · 11-24-2010, 10:50 PM

Originally posted by SPA

Check FW version. I have similar problem with my 35/2.8 Macro. But with last two version of firmware, the AF is more stable.

edit: I just saw that you use last FW. You can try set it again. Some time helps.

I think it will be far less "noticable" with lenses F2.8 and narrower. But I'd be very comfortable with a F2.8 lens, as my experience with the 3 lenses virtually disappeared with and after F2.8

icypepsi · 11-24-2010, 10:54 PM

Originally posted by Digitalis

I had some focusing issues with my sigma 100-300mm f/4 I adjusted it but it would still drift in and out from week to week. In the end I just gave up and reset it to +1 and strangely it seems to have settled down.....

I don't know if you read my experience about the K7 not saving the microfocus adj. even when it says "Saved". I had the same problem, until I discovered it wasn't. Same thing, I used to feel it magically settles for some one value. But the weekly drifting... stranger still!! Maybe some more testing should tell what it is.

looktime · 12-05-2010, 02:35 PM

I tried three copies of Sigma 50mm f1.4. All them have FF issue. The question is if Sigma management knows this issue?

Ratmagiclady · 12-05-2010, 02:52 PM

It'd be hard to convince me I wanted a Sigma 50 1.4 when just the Pentax-made 50's are such a candy store, anyway.

Tried an FA 50? I just love em.

For 28-30ish fast-ness, that's still another matter. I considered looking for the Sigma 30mm, which seems fairly nice, though I went with the 28/1.8, instead, cause it has more useful-to-me qualities. (Despite a size that often makes me dream of FA 31s

)

Three lenses are a lot to have the same issue: I presume you're sure it's not caused by something else? Sigma seems to be making nice stuff lately.

looktime · 12-06-2010, 10:15 AM

The problem is FA 50 1.4 is not so good at wide open. But compared with my front focused Sigma 50mm, I would rather choose FA 50.

Originally posted by Ratmagiclady

It'd be hard to convince me I wanted a Sigma 50 1.4 when just the Pentax-made 50's are such a candy store, anyway.

Tried an FA 50? I just love em.

For 28-30ish fast-ness, that's still another matter. I considered looking for the Sigma 30mm, which seems fairly nice, though I went with the 28/1.8, instead, cause it has more useful-to-me qualities. (Despite a size that often makes me dream of FA 31s

)

No, I have other lenses. None of them has focus issue.

Three lenses are a lot to have the same issue: I presume you're sure it's not caused by something else? Sigma seems to be making nice stuff lately.

icypepsi · 03-29-2011, 10:55 AM

For those wondering what the hell this guy did eventually, I returned the Sigma 50mm F1.4 HSM and went on the vacation without it

But after I got back, I waited and purchased the Sigma 85mm F1.4 a week ago and see similar problems, but much less pronounced and much more acceptable. Actually, I have another issue with the 85 in that I must be having a bad copy. I discussed it in this thread. Please take a look, you may have an answer!

WerTicus · 03-30-2011, 01:02 AM

i've never had any luck with sigma's... in fact i wont bother trying them again... the DA 55 for me!

icypepsi · 03-30-2011, 07:13 AM

Originally posted by WerTicus

i've never had any luck with sigma's... in fact i wont bother trying them again... the DA 55 for me!

I hope that's not the case with me. Coz, the previous time, this problem was shown by the DA 55 also. Besides, the DA 55, Sigma too has some fantastic optics. I would surely have gone for the FA 77, if it were SDM.

11-24-2010, 06:27 AM	#35
philippe Veteran Member Join Date: Apr 2008 Location: Flanders Fields Posts: 463	I have an other issue with my Sigmalux I didn't mention before. In LR3.3 this lens is 'recognized' as a 70-200 mm F2.8 EX DG Macro HSM II zoom . So the Lens Profile corrections are done for the wrong lens AND as mounted on a Nikon camera, go figure, a Nikon ! That 'Nikon thing' is indeed a very strange turn of events ! Last edited by philippe; 11-24-2010 at 08:30 AM.

03-29-2011, 10:55 AM	#43
icypepsi Forum Member Join Date: Sep 2009 Location: New Jersey Posts: 81 Original Poster	I bought the Sigma 85mm F1.4 For those wondering what the hell this guy did eventually, I returned the Sigma 50mm F1.4 HSM and went on the vacation without it But after I got back, I waited and purchased the Sigma 85mm F1.4 a week ago and see similar problems, but much less pronounced and much more acceptable. Actually, I have another issue with the 85 in that I must be having a bad copy. I discussed it in this thread. Please take a look, you may have an answer!

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11-21-2010, 12:55 AM	#31
Laurentiu Cristofor Banned Join Date: Nov 2009 Location: WA Photos: Albums Posts: 3,055	AF happens with the lens wide open. So it doesn't matter whether you can see the DOF changes or not as you stop down. DOF is thinnest at 1.4 - if the AF system can focus there, that will work for 2.8 too. Of course, this doesn't take into account focus shift - that's the problem you've been exploring in this thread and one that AF systems don't seem to compensate for. That happens because AF determines focus at 1.4 and then stops down to 2.8, but at that aperture, the focusing is incorrect, so you'll get back focus or front focus. With the proper lens-camera interface, the lens manufacturer could encode the focus adjustment for a lens with focus shift, but it doesn't sound like this thing is done currently.

11-22-2010, 12:52 PM	#32
Rin Forum Member Join Date: Nov 2010 Posts: 87	Are the current variations of the Sigma 50mm 1,4 without issues or is front and back focus still very common.

11-22-2010, 02:47 PM	#33
SPA New Member Join Date: Mar 2008 Location: Bulgaria Photos: Gallery Posts: 18	Check FW version. I have similar problem with my 35/2.8 Macro. But with last two version of firmware, the AF is more stable. edit: I just saw that you use last FW. You can try set it again. Some time helps.

11-23-2010, 11:27 AM	#34
Rin Forum Member Join Date: Nov 2010 Posts: 87	tomorrow i will receive the same lens and a K5, i wonder how it will eprform i can return it within 2 weeks anyway

11-24-2010, 06:32 AM	#36
Digitalis Site Supporter Join Date: Mar 2009 Location: Melbourne, Victoria Photos: Gallery Posts: 11,694	I had some focusing issues with my sigma 100-300mm f/4 I adjusted it but it would still drift in and out from week to week. In the end I just gave up and reset it to +1 and strangely it seems to have settled down. I'll also mention that my sigma 100-300mm f/4 is also recognised by light room as a sigma 70-200mm f/2.8 - which is very annoying when I want to do lens based image searches. knock on wood.

11-24-2010, 10:48 PM	#37
icypepsi Forum Member Join Date: Sep 2009 Location: New Jersey Posts: 81 Original Poster	Originally posted by Rin Are the current variations of the Sigma 50mm 1,4 without issues or is front and back focus still very common. Sorry, I've been a bit busy. Well, the issue is definitely there. But not just with Sigma. I think it is "noticable" with lenses wider than F2.8. Congratulations. So, how's your K5 + Sigma turning out? As for me, I would settle with that problem, coz there's no cure as of today. Like an online article pointed out, getting used to the lens' behavior, manually! I hate it, but I really really love the way a prime's picture's look. That "raw" brightness and sharpness. For myself, I also discovered that 50mm was a bit short for my style of shooting. So I'm actually waiting for the Sigma 85mm F1.4 HSM. They seem to have solve this "focus plane shift" problem; of some online posts I read. They are on sale right now, but I just don't have the time to buy one and test... So, for me it's going to be this new year. Money's intact for it! I'm also considering the FA 77mm F1.8. Seems more sharper, with screw-drive AF. Last edited by icypepsi; 11-24-2010 at 11:03 PM.

11-24-2010, 10:50 PM	#38
icypepsi Forum Member Join Date: Sep 2009 Location: New Jersey Posts: 81 Original Poster	Originally posted by SPA Check FW version. I have similar problem with my 35/2.8 Macro. But with last two version of firmware, the AF is more stable. edit: I just saw that you use last FW. You can try set it again. Some time helps. I think it will be far less "noticable" with lenses F2.8 and narrower. But I'd be very comfortable with a F2.8 lens, as my experience with the 3 lenses virtually disappeared with and after F2.8

11-24-2010, 10:54 PM	#39
icypepsi Forum Member Join Date: Sep 2009 Location: New Jersey Posts: 81 Original Poster	Originally posted by Digitalis I had some focusing issues with my sigma 100-300mm f/4 I adjusted it but it would still drift in and out from week to week. In the end I just gave up and reset it to +1 and strangely it seems to have settled down..... I don't know if you read my experience about the K7 not saving the microfocus adj. even when it says "Saved". I had the same problem, until I discovered it wasn't. Same thing, I used to feel it magically settles for some one value. But the weekly drifting... stranger still!! Maybe some more testing should tell what it is.

12-05-2010, 02:35 PM	#40
looktime Inactive Account Join Date: Dec 2010 Posts: 16	I tried three copies of Sigma 50mm f1.4. All them have FF issue. The question is if Sigma management knows this issue?

12-05-2010, 02:52 PM	#41
Ratmagiclady Veteran Member Join Date: Nov 2008 Location: GA Photos: Gallery \| Albums Posts: 13,563	It'd be hard to convince me I wanted a Sigma 50 1.4 when just the Pentax-made 50's are such a candy store, anyway. Tried an FA 50? I just love em. For 28-30ish fast-ness, that's still another matter. I considered looking for the Sigma 30mm, which seems fairly nice, though I went with the 28/1.8, instead, cause it has more useful-to-me qualities. (Despite a size that often makes me dream of FA 31s ) Three lenses are a lot to have the same issue: I presume you're sure it's not caused by something else? Sigma seems to be making nice stuff lately.

12-06-2010, 10:15 AM	#42
looktime Inactive Account Join Date: Dec 2010 Posts: 16	The problem is FA 50 1.4 is not so good at wide open. But compared with my front focused Sigma 50mm, I would rather choose FA 50. Originally posted by Ratmagiclady It'd be hard to convince me I wanted a Sigma 50 1.4 when just the Pentax-made 50's are such a candy store, anyway. Tried an FA 50? I just love em. For 28-30ish fast-ness, that's still another matter. I considered looking for the Sigma 30mm, which seems fairly nice, though I went with the 28/1.8, instead, cause it has more useful-to-me qualities. (Despite a size that often makes me dream of FA 31s ) No, I have other lenses. None of them has focus issue. Three lenses are a lot to have the same issue: I presume you're sure it's not caused by something else? Sigma seems to be making nice stuff lately.

03-30-2011, 01:02 AM	#44
WerTicus Veteran Member Join Date: Mar 2009 Location: Perth Australia Photos: Albums Posts: 1,514	i've never had any luck with sigma's... in fact i wont bother trying them again... the DA 55 for me!

03-30-2011, 07:13 AM	#45
icypepsi Forum Member Join Date: Sep 2009 Location: New Jersey Posts: 81 Original Poster	Originally posted by WerTicus i've never had any luck with sigma's... in fact i wont bother trying them again... the DA 55 for me! I hope that's not the case with me. Coz, the previous time, this problem was shown by the DA 55 also. Besides, the DA 55, Sigma too has some fantastic optics. I would surely have gone for the FA 77, if it were SDM.

Should I return my Sigma 50mm 1.4 HSM ?

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