Sigma 50mm: Marmite Bokeh

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Archive 2008 · Sigma 50mm: Marmite Bokeh

joekraft
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p.25 #1 · Sigma 50mm: Marmite Bokeh

Would/did that do anything for erratic focusing at longer distances? I had my lens calibrated, and it seems like it could be a little better. When it's on, it's good, but it is a little inconsistent.
ovredal73 wrote:
Jonas, try having Canon calibrate your camera to their in house reference lens. It turned out the problem for me was the camera, not the lens. The Canon repair guy acknowledged that my camera was completely misaligned, leaving the focus point way out.

Edited on Feb 28, 2009 at 11:06 PM · View previous versions

Feb 28, 2009 at 11:04 PM

Jonas B
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p.25 #2 · Sigma 50mm: Marmite Bokeh

ovredal73 wrote:
Jonas, try having Canon calibrate your camera to their in house reference lens. It turned out the problem for me was the camera, not the lens. The Canon repair guy acknowledged that my camera was completely misaligned, leaving the focus point way out.

My 5D was calibrated by Canon Sweden between the two visits it made, together with the lens, at Sigma Scandinavia. There was no improvement; the camera and lens combo still focused at random (my Canon lenses worked fine). That was a very unfortunate result and it later made me return the lens to the shop. Also see my next reply.

Mar 01, 2009 at 04:11 PM

Jonas B
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p.25 #3 · Sigma 50mm: Marmite Bokeh

joekraft wrote:
Would/did that do anything for erratic focusing at longer distances? I had my lens calibrated, and it seems like it could be a little better. When it's on, it's good, but it is a little inconsistent.

It didn't help my 5D/Siggy50 combo. I can't tell why really. I reallt tried to coop with the lens as it optically is my fast 50mm favourite (and I have tried about 10 different 50/1.4 lenses).

Here are, loosely presented, some of the test images I finally gave to my vendor:

I gave up. I do however intend to buy the lens again and try it with the 5DMkII at some time. Lol, if there is life there is hope.

Mar 01, 2009 at 04:19 PM

joekraft
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p.25 #4 · Sigma 50mm: Marmite Bokeh

Well Jonas, it sounds like you exhausted your avenues to fix it, that is too bad. Thanks for the information though. On the 70m test, were you focusing on the bike? I'm not sure I would expect very good results on that one, given how small the target would be.

Mar 01, 2009 at 04:39 PM

Jonas B
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p.25 #5 · Sigma 50mm: Marmite Bokeh

joekraft wrote: (...)On the 70m test, were you focusing on the bike? I'm not sure I would expect very good results on that one, given how small the target would be.

I used the center focusing point only aiming it to the line behind the bike. As there was nothing in the way between the camera and the target the situation was not a problem. Camera on tripod, focus was locked every time with no hesitation.
At approx 70m one would expect better, no?

One of my main concerns was that i couldn't trust the AF when shooting in daily life. Portraits were all OK and possible to adjust manually most of the times, Shooting in the street, for example at something a bit away or something at the other side of the street... No, it just didn't work.
Maybe latter lenses are better. That is what I hope at least. I was an early adopter.

Mar 01, 2009 at 05:34 PM

joekraft
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p.25 #6 · Sigma 50mm: Marmite Bokeh

I'm not sure, and technically, this may be well within spec for the camera, but my own experience with my 5D is that something that small at 70m is going to be iffy at best, that's all. I'm not saying there weren't problems with your particular lens, but I'm not sure anything that wide can *reliably* focus on a target that small at that distance. Like I said, just going from my experience with all my other lenses on this camera, others may have a different opinion.
Jonas B wrote:
joekraft wrote: (...)On the 70m test, were you focusing on the bike? I'm not sure I would expect very good results on that one, given how small the target would be.

I used the center focusing point only aiming it to the line behind the bike. As there was nothing in the way between the camera and the target the situation was not a problem. Camera on tripod, focus was locked every time with no hesitation.
At approx 70m one would expect better, no?

Mar 01, 2009 at 06:44 PM

Jonas B
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p.25 #7 · Sigma 50mm: Marmite Bokeh

joekraft wrote:
I'm not sure, and technically, (...) but I'm not sure anything that wide can *reliably* focus on a target that small at that distance.

I understand what you mean. The way I see is that the exact size of the thing I aimed at is not important. I expected a repeatable result. This is not far from "infinity" and with the camera on tripod I think it "saw" and locked at the same target (whatever it was) for every image.

When I said I expected better I was thinking of a more consistent result. Now the 70m target gave the same disappointing result as the tries at shorter distances; quite varying focusing.

Another, and longer lens, gave another result:

I liked that better. The EF85 also showed to focus correctly in my everyday common use.

The test series above were al taken after the calibration done by first Canon (the camera body) and then Sigma (the lens on that body). They are better than the initial results. My impression when giving up on the lens was that I got some front focusing on short distances, nearly OK results at 2m and more backfocusing at longer distances. Sigma calibrates the lenses at a distance of 40x the focal length, which in this case is 2m.

regards, /Jonas

Mar 01, 2009 at 07:12 PM

ovredal73
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p.25 #8 · Sigma 50mm: Marmite Bokeh

Jonas B wrote:
ovredal73 wrote:
Jonas, try having Canon calibrate your camera to their in house reference lens. It turned out the problem for me was the camera, not the lens. The Canon repair guy acknowledged that my camera was completely misaligned, leaving the focus point way out.

My 5D was calibrated by Canon Sweden between the two visits it made, together with the lens, at Sigma Scandinavia. There was no improvement; the camera and lens combo still focused at random (my Canon lenses worked fine). That was a very unfortunate result and it later made me return the lens to the shop. Also see my next reply.

Surprising and really unfortunate. Hope you get it again with the 5d2.

Mar 01, 2009 at 08:42 PM

Jonas B
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p.25 #9 · Sigma 50mm: Marmite Bokeh

ovredal73 wrote:
Surprising and really unfortunate. Hope you get it again with the 5d2.

Oh, I'm quite sure that will happen.The Sigma 50/1.4 is made for a certain sort of bokeh aficionados and combined with the performance wide open I see no option really.

Cheers, /Jonas

Mar 01, 2009 at 11:06 PM

Bounce o1
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p.25 #10 · Sigma 50mm: Marmite Bokeh

have it on my D700. like it better than the nikkor 1.4G . was worth the extra $$ to me
bounce

Mar 06, 2009 at 09:02 AM

mh2000
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p.25 #11 · Sigma 50mm: Marmite Bokeh

Jonas, did you do a similar test with a Canon 50 vs. the Sigma and your camera?

Mar 06, 2009 at 07:46 PM

abam
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p.25 #12 · Sigma 50mm: Marmite Bokeh

i wouldn't have gotten this lens if i didn't have a body with the af micro adjust feature. in line with lots of other online experiences, i had to dial in a considerable amount of adjustment.

(+11 got mine spot on. it is razor sharp now, though.)

Mar 11, 2009 at 09:55 PM

Jonas B
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p.25 #13 · Sigma 50mm: Marmite Bokeh

mh2000 wrote:
Jonas, did you do a similar test with a Canon 50 vs. the Sigma and your camera?

I'm sorry for the late reply. I missed your post.

Yes I did. That was prior to the first try by Sigma Scandinavia to calibrate the lens. By then I had the 450D, the EF50/1.4 and the Sigma 50. The 450D didn't focus exact with the EF50 but good enough, and consistent. There was a clear difference.

I never tried the 70m target with the EF50 though.

Mar 11, 2009 at 11:25 PM

pdmphoto
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p.25 #14 · Sigma 50mm: Marmite Bokeh

I'm guessing your result wouldn't have been any better with the Canon EF50. I think as Joe and others have mentioned, the AF target is just too small (considering the distance) for a 50mm lens. Comparing it to the 85mm results is not realistic because the AF target is almost twice the size (at the same distance).

Mar 12, 2009 at 05:49 PM

Jonas B
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p.25 #15 · Sigma 50mm: Marmite Bokeh

pdmphoto wrote:
I'm guessing your result wouldn't have been any better with the Canon EF50.

Hi,

Perhaps it wouldn't. As I said i didn't do a direct comparison on this distance and target. I know the EF50/1.4 did better than the Sigma50/1.4 at 20m.

A target at approx 70m may or may not have much with real photography to do. 20m however has, at least for somebody shooting in the streets in evenings (wide open).

pdmphoto wrote:
I think as Joe and others have mentioned, the AF target is just too small (considering the distance) for a 50mm lens. Comparing it to the 85mm results is not realistic because the AF target is almost twice the size (at the same distance).

I agree the target was pretty small.
The camera was on a tripod and the camera/lens combo happily locked at something every time I focused. Maybe the inconsistency is more interesting than the exact focus point. I was, frankly, a bit surprised by the result at approx 70m. At that distance we should have some DOF to work with, also at f/1.4. Yet the camera and lens combo managed to screw up considerably and focus beyond infinity. I guess there is something I don't understand.

pdmphoto wrote:
Comparing it to the 85mm results is not realistic because the AF target is almost twice the size (at the same distance).

I'm no AF guru... How big does a target has to be compared to offer some contrast for the PDAF system to lock on? When taking a quick shot of something at infinity, how big is it supposed to be (if there is no horizon line)?

regards, /Jonas

Mar 12, 2009 at 10:13 PM

luigi.malago
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p.25 #16 · Sigma 50mm: Marmite Bokeh

Hi to all. I just go my new Sigma 1.4 50mm and I'm trying to see if it has some kind of problem in order to decided whether or not it is the case to return it. I think my copy does not have focus problem, but I'm concerned about sharpness wide open. I put different series of tests on this thread:

link

I'm not going to link all of them here, since the other thread is pretty long.
It's not in eglish, but you can just look at the pictures ;-)

in particular, take a look at these
all 1.4

This image is copyrighted by the owner

should I expect something different form my sigma?

I have a 450D. All shots taken with tripod, 100 ISO, mirror locked, 2 sec delay.

thanks alot,
bye
Luigi

Jun 21, 2009 at 10:41 PM

ingardj
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p.25 #17 · Sigma 50mm: Marmite Bokeh

Do you have any non-100% images? I think it looks good..

Jun 21, 2009 at 11:03 PM

luigi.malago
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p.25 #18 · Sigma 50mm: Marmite Bokeh

Hi ingardj, and thanks for replying. For all images (and even those I added in the thread I linked in the previous post) to get the non cropped version, just replace "sigma" with "sigma2" in the url of the image. For the images I linked above, the urls are

cropped

www.ma5.it/luigi/sigma/IMG_1015.JPG
www.ma5.it/luigi/sigma/IMG_1128.JPG
www.ma5.it/luigi/sigma/IMG_1142.JPG
www.ma5.it/luigi/sigma/IMG_1190.JPG

non cropped

www.ma5.it/luigi/sigma2/IMG_1015.JPG
www.ma5.it/luigi/sigma2/IMG_1128.JPG
www.ma5.it/luigi/sigma2/IMG_1142.JPG
www.ma5.it/luigi/sigma2/IMG_1190.JPG

thanks a lot,
luigi

Jun 22, 2009 at 12:37 PM


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