Sigma 50mm: Marmite Bokeh

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Archive 2008 · Sigma 50mm: Marmite Bokeh

thrice
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p.22 #1 · Sigma 50mm: Marmite Bokeh

ugh I guess cos this thread is really long no one bothers to read the earlier posts but this much has been established:

1. The issue is back focusing when focusing beyond 10' on full frame bodies
2. Many copies focus perfectly on crop frame bodies
3. The more common issue (if there is one) on crop bodies is front focusing
4. Calibration is NOT the issue - calibrated full frame bodies matched to calibrated sigma 50/1.4's get the same issue. It is not correctable with lens profiles in mark III bodies.

Let's try to not cover the same ground

Oct 19, 2008 at 10:13 AM

ulrikft
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p.22 #2 · Sigma 50mm: Marmite Bokeh

Are we all agreeing that it is a canon problem too? Or have noink-users also had problems?

Oct 19, 2008 at 12:00 PM

ovredal73
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p.22 #3 · Sigma 50mm: Marmite Bokeh

Thrice, thanks for recapping - If you dont mind I will use your recap to start a new thread as your point about this thread becoming hard to keep track of is very valid.

And Ulrik - I believe the Nikons are fine, but only from reading Nikon forum threads talking about the lens in general, not mentioning any problems....

Oct 19, 2008 at 02:20 PM

ravon
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p.22 #4 · Sigma 50mm: Marmite Bokeh

ovredal73 wrote:
Ravon, thanks for posting. What is the first 4 digits in your serial number?
Your copy or possibly the combo 400D + Sig50 seems to work. Maybe there is no issue with crop sensors? Could it be a specific problem with 5D plus this lens?
I have now tested 4 different copies on my 5D and all of them are severly out of whack.

You're welcome. The serial number of my Sigma 50 mm is 1006###.

My combo works really great, I have tested the Canon f/1.8 mk1 and I took a brief look at the f/1.4 and my experience sofar is that the Sigma outperforms both Canon lenses.

Simply assuming that Canon does a flawless job in camera's or lenses does not make much sense to me. Have you ever tested your Sigma 50 mm on a crop sensor camera or on another 5D?

Oct 19, 2008 at 04:11 PM

ovredal73
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p.22 #5 · Sigma 50mm: Marmite Bokeh

ravon wrote:
ovredal73 wrote:
Ravon, thanks for posting. What is the first 4 digits in your serial number?
Your copy or possibly the combo 400D + Sig50 seems to work. Maybe there is no issue with crop sensors? Could it be a specific problem with 5D plus this lens?
I have now tested 4 different copies on my 5D and all of them are severly out of whack.

Have you ever tested your Sigma 50 mm on a crop sensor camera or on another 5D?

Neither unfortunately. I dont have access to another 5D, but I will try it on a 350D tomorrow, before returning it. I guess the problem is with FF only, so I expect it to work nicely on the 350. But I use FF...

Oct 19, 2008 at 07:42 PM

Drew_Persson
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p.22 #6 · Sigma 50mm: Marmite Bokeh

Maybe it's already been posted (didn't read all 22 pages), but here's the Sigma MTF wide open at 10 and 30. Pretty impressive for f/1.4.

With an APS-C sensor body, the Sigma curves don't drop much until just past the corners of the sensor.

This image is copyrighted by the owner

And the Canon 50mm f/1.4 (ignore blue f/8 lines to compare). The Canon dips well before the corners of the sensor at 13mm or so.

This image is copyrighted by the owner

Edited on Oct 22, 2008 at 08:16 AM · View previous versions

Oct 22, 2008 at 05:23 AM

rico
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p.22 #7 · Sigma 50mm: Marmite Bokeh

It's a shame this Sigma has focus problems similar to the Canon EF 50/1.2L (a real letdown). I continue to limp along with the EF 50/1.4 - lumpy construction, lousy bokeh, lifeless @ f/1.4. Next up for us fans of the fast 50 is Nikon's AF-S redesign. My fingers are crossed...

Oct 22, 2008 at 07:12 AM

Drew_Persson
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p.22 #8 · Sigma 50mm: Marmite Bokeh

Odd that a lens can have AF issues, I've used a DSLR with an AF-confirm chip adapter on a view camera with a large format lens and the focus is spot-on. No connection between the camera and the lens whatsoever, just adjust the standard until the AF light flashes and the body beeps.

Seems like the lens should be irrelevant, the camera knows when to stop the lens focus drive. Maybe the lens coasts past the optimum point.

Oct 22, 2008 at 08:09 AM

trumpet_guy
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p.22 #9 · Sigma 50mm: Marmite Bokeh

Seems like the lens should be irrelevant, the camera knows when to stop the lens focus drive. Maybe the lens coasts past the optimum point.

That may be part of the problem. The Sigma 50/1.4 has relatively heavy
glass to move, and it moves it pretty quickly.

But.....
I've tried pumping the * button to repeatedly AF the thing, and once it has locked
onto the misfocused range, it stays there, so I expect there is still a control
algorithm problem.

Oct 22, 2008 at 08:12 AM

ravon
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p.22 #10 · Sigma 50mm: Marmite Bokeh

rico wrote:
It's a shame this Sigma has focus problems similar to the Canon EF 50/1.2L (a real letdown). I continue to limp along with the EF 50/1.4 - lumpy construction, lousy bokeh, lifeless @ f/1.4. Next up for us fans of the fast 50 is Nikon's AF-S redesign. My fingers are crossed...

You're jumping into conclusions... This 50mm Sigma seems to have problems with a couple of 5D bodies. On my 400D the Sigma works flawless and produces great image quality.

Oct 22, 2008 at 09:49 AM

ovredal73
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p.22 #11 · Sigma 50mm: Marmite Bokeh

I have now had Canon adjust my 5D to factory specs, using their own in house ref lens (whatever that is).
The Sigma went from completely out at mostly any distance to display spot-on focus at every distance.
I realized this possibility when suddenly my 85L was as out as the Sigma. I havent used the 85L much the last couple of years, since I started shooting with alts.

I will post more on this later, including test images, to show what happened. It is quite amazing how way out my 5D was, even the technician was somewhat surprised by it. I wonder if all my alt lens use could be to blame for this.

My 1006xxx Sigma is now a complete babe on my 5D

EDIT: That is, under less ecstatic scrutinization, it now front focuses a bit. I will turn the lens in at the Sigma dealer tomorrow and have it adjusted. Then, I think it should all be great...

Oct 22, 2008 at 12:32 PM

ravon
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p.22 #12 · Sigma 50mm: Marmite Bokeh

Now that's good news!

Oct 22, 2008 at 02:59 PM

ovredal73
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p.22 #13 · Sigma 50mm: Marmite Bokeh

Even my 50 macro was noticably out of focus before turning in the camera. I am afraid all this old lens stuff have some negative consequences for the modern high tech equipment we have. Or it could just be the mirror banging into the rear of my precious Rokkor a couple of times too many....

Oct 22, 2008 at 03:44 PM

Drew_Persson
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p.22 #14 · Sigma 50mm: Marmite Bokeh

Just received my copy, serial 1007xxx.

Some 100% crop focus test shots using 1Ds2:

At 25 feet (red arrow pointing at focus target)

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At 5 feet

Disregard exposure, which was +1EV.

Focus seems right on the money! Definitely need your focus target to stand out against the background though, initially I put the target on a cinder block seam and the AF picked up the seam instead of the target.

Note the purple fringing before focus plane and green after, to be expected I suppose with CA of about 1/3 pixel. Very nice lens though, well-built and solid, good match for the 1Ds2. Just need to check out the bokeh now!

Oct 23, 2008 at 12:26 AM

Drew_Persson
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p.22 #15 · Sigma 50mm: Marmite Bokeh

A bokeh shot, DON'T get hung up on the laser leveler sharpness - this was shot in gusty 40mph Santa Ana winds. The laser leveler was moving, the camera was moving, etc.

But the bokeh doesn't care about wind, and IMHO it's pretty darn smooth. Two thumbs up.

In case you were wondering this is a parking lot with some cars in the background (back of pickup truck on right), a residential area behind with foliage, and brown grassy hills about four miles in the distance. Setting sun and long shadows for lighting. You can't even see all of the power and telephone lines crossing the blue sky, but there are lots of them. Poof, they're gone. I think I'm going to enjoy this lens.

Oct 23, 2008 at 12:48 AM

Drew_Persson
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p.22 #16 · Sigma 50mm: Marmite Bokeh

Wide-open on 40D, in camera JPEG, focus roughly on tip of nose, quite backlit, some movement possible (this kitten is a maniac and never stops moving).

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100% crop

Oct 27, 2008 at 05:20 AM

thrice
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p.22 #17 · Sigma 50mm: Marmite Bokeh

Lovely diffuse blur in the background, quite a bit of purple fringing though, but to be expected on a large aperture 50 (except the Summilux-M 50 1:1.4 which is apochromatic).

Oct 27, 2008 at 06:04 AM

Sam N
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p.22 #18 · Sigma 50mm: Marmite Bokeh

ovredal73 wrote:
Sam, how is yours for AF?

Works perfectly.

The performance at near MFD is not as good as it is further away. This lens is great for portraits and I love the bokeh.

thrice wrote:
ugh I guess cos this thread is really long no one bothers to read the earlier posts but this much has been established:

1. The issue is back focusing when focusing beyond 10' on full frame bodies
2. Many copies focus perfectly on crop frame bodies
3. The more common issue (if there is one) on crop bodies is front focusing
4. Calibration is NOT the issue - calibrated full frame bodies matched to calibrated sigma 50/1.4's get the same issue. It is not correctable with lens profiles in mark III bodies.

Let's try to not cover the same ground

The flaws in the paint-can test have already been pointed out. I'm sure some people still have some sort of focusing issues, but I think it's silly to say that a lens model works on crop bodies but not on full frame for some mystical reason. As for calibration, apparently it was the issue in at least one case.

BTW, although it may be the best performing 50mm and have very few CAs of any kind, the 50mm Summilux ASPH is not apochromatic. You might be thinking of the 70/2 or 90/2.

Oct 28, 2008 at 10:08 PM

thrice
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p.22 #19 · Sigma 50mm: Marmite Bokeh

The Summilux 50 is apo, it's just not advertised. It is the same optical formula as the 75/1.4 Aspherical APO with the addition of one optical (non-apochromatic) element. I read an interview with Walter Mandler that clearly said so...

EDIT Here's the interview with Peter Karbe (not Mandler, my bad) where he explains the Summilux 50/1.4 being APO.

http://dfarkas.blogspot.com/2008/09/photokina-2008-day-2-taking-it-easy-and.html

Oct 28, 2008 at 10:23 PM

nana kofi
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p.22 #20 · Sigma 50mm: Marmite Bokeh

I can say for a fact that this lens is awesome on the 5d. The Renee fashion show photos on my blog were taken in low light conditions and the lens didn't hunt one bit. Link is: http://aphotojournalist.blogspot.com

Nov 16, 2008 at 12:07 AM

thrice
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p.22 #21 · Sigma 50mm: Marmite Bokeh

nana kofi wrote:
I can say for a fact that this lens is awesome on the 5d. The Renee fashion show photos on my blog were taken in low light conditions and the lens didn't hunt one bit. Link is: http://aphotojournalist.blogspot.com

What's your serial if you don't mind me asking?

EDIT: Also all the exif info is stripped out of your pics? could you please share a 100% crop of the face from this pic? Thanks

Edited on Nov 16, 2008 at 09:39 AM · View previous versions

Nov 16, 2008 at 01:46 AM

bluetsunami
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p.22 #22 · Sigma 50mm: Marmite Bokeh

The Sigma 50mm definitely has way more of a contrast punch, wide open, than the Canon 1.4 (seen it already stated, thought I'd throw my opinion in that lot too). Sharper wide open also, which is fantastic.

Nov 16, 2008 at 02:09 AM

Pavel
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p.22 #23 · Sigma 50mm: Marmite Bokeh

Well, I've owned several samples of Sigma's and the only thing that bothered me was focus issues and the occasional need to re-chip. But that was when I shot with canon ... and frankly I always had focus issues of some sort on the platform for the way I shoot - so it was simply of problem of a small magnitude of degree.

But I've been a bit leary of Sigma's since despite my logical side.
I was going to buy the Zeiss soon .... but after seeing this I'm going with the sigma.

I happen to like my bokeh to disappear. Fashion and portraits simply have more impact where you want it with unobtrusive details. But also there is the simple fact that my Nikon 50 is decent, but also it is very similar to all the others. Only a photographer gets excited about the differences so subtle among each of these lenses. There simply are no visible difference until one makes a career of looking for them instead of shooting photographs. Only the sigma stands out. Only the Sigma stand out to the degree that "normal" people see it, plain as day. Only the sigma has a completely different signature.
That makes it worth it's weight in gold.

Count me as a surprised sigma convert.

Oh ... and than you very much for this thread!

Dec 14, 2008 at 04:19 PM

Andi Dietrich
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p.22 #24 · Sigma 50mm: Marmite Bokeh

I agree with Pavel, the Sigma has a different signature. It s well worth the price, on the other side its not really as sharp as other lenses stopped down and it may have a little less DOF than a good prime. The Sigma does not stand a chance at f5.6 against my fast ZF 50. Just an observation

Dec 14, 2008 at 04:44 PM

ovredal73
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p.22 #25 · Sigma 50mm: Marmite Bokeh

I love my Sigma - now

It´my go-to lens when needing AF.

Dec 14, 2008 at 04:47 PM


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