Approve the Cookies
This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies and our Privacy Policy.
OK
Index  •   • New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Guest
New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Register to forums    Log in

 
FORUMS Canon Cameras, Lenses & Accessories Canon EF and EF-S Lenses 
Thread started 24 Apr 2009 (Friday) 07:50
Search threadPrev/next
sponsored links
(this ad will go away when you log in as a registered member)

Soft Sigma 50mm 1.4 HSM

 
AngryCorgi
-Bouncing Boy- a POTN peion
Avatar
11,543 posts
Likes: 2
Joined Aug 2005
Location: Surrounded by bunnies, squirrels and a couple of crazy corgis in NoVA...
     
Apr 24, 2009 09:46 |  #16

bacchanal wrote in post #7795104 (external link)
How can you be so sure it's not front focusing as the bottle is round and there is nothing in front of the target (the "C"). It's possible that we're just seeing the tail end of the dof range. Anyway, I suppose this could be easily verified with live view + MF.

The halation in the f/1.4 shot sure makes it look like there is something wrong with the lens though.

Even though the bottle is square (as identified just now by the OP), you can see the f/1.4 shot shows purple LoCA in front and green LoCA in back with the middle area (the in-focus area) still soft. Anytime you have the red/purple LoCA on a shot, you are definitely not front-focusing. Front-focusing should yield a green glow around the focus-target, assuming the lens is not apochromatic.


AngryCorgi (external link) (aka Tom) ...Tools...

...Knowledge is knowing that a tomato is a fruit, Wisdom is knowing not to include it in a fruit salad...

  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)
phigment
THREAD ­ STARTER
Member
230 posts
Likes: 2
Joined Jan 2009
Location: Waterloo, Ontario, Canada
     
Apr 24, 2009 09:48 |  #17

AngryCorgi wrote in post #7795317 (external link)
Even though the bottle is square (as identified just now by the OP), you dan see the f/1.4 shot shows purple LoCA in front and green LoCA in back with the middle area (the in-focus area) still soft. Anytime you have the red/purple LoCA on a shot, you are definitely not front-focusing. Front-focusing should yield a green glow in the LoCA.

You hit it spot on. When I initially tested this lens with AF, I was always getting a green glow. So this lens has two issues, front focus and softness. Looks like I'll be contacting Sigma.


A7R, Firin 20mm, CV 21/4, CV 40/1.4, 100ZE, 300 4LIS, Tamron 150-600, Jupiter 8, RX100 IV

  
  LOG IN TO REPLY
phigment
THREAD ­ STARTER
Member
230 posts
Likes: 2
Joined Jan 2009
Location: Waterloo, Ontario, Canada
     
May 12, 2009 18:55 as a reply to  @ phigment's post |  #18

Well, I got my lens back last friday. It took one week from when I sent to it when I got it back.

The Autofocus seems to be better, but it is still pretty soft wide open when pixel peeping.

I have a quick question though. When stopping down the aperture, is the focal distance expected to change? That's exactly what I am seeing.

In the attached images, it appears that the focal point is around the "vitamin a" line for f/1.4, but then when going to f/3.2 it suddenly changes to the "cholesterol" line. And the text directly below the nutritional info seems blurrier in the f/3.2 version than in f/1.4.

These pictures were taken using a tripod and it is consistently reproducible.

f/1.4


HOSTED PHOTO
please log in to view hosted photos in full size.


f/3.2

HOSTED PHOTO
please log in to view hosted photos in full size.


A7R, Firin 20mm, CV 21/4, CV 40/1.4, 100ZE, 300 4LIS, Tamron 150-600, Jupiter 8, RX100 IV

  
  LOG IN TO REPLY
AlanU
Cream of the Crop
7,445 posts
Gallery: 126 photos
Likes: 1274
Joined Feb 2008
Location: Vancouver, BC
     
May 12, 2009 19:06 |  #19

Have you tried tweeking with AF micro adjust?


5Dmkiv |5Dmkiii | 24LmkII | 85 mkII L | | 16-35L mkII | 24-70 f/2.8L mkii| 70-200 f/2.8 ISL mkII| 600EX-RT x2 | 580 EX II x2 | Einstein's
Fuji - gone
Sony 2 x A7iii w/ Sigma MC-11 adapter | GM16-35 f/2.8 | Tamron 28-75 f/2.8 | GM70-200 f/2.8 |Sigma Art 24 f/1.4 | Sigma ART 35 f/1.2 | FE85 f/1.8 | Sigma ART 105 f/1.4 | Godox V860iiS & V1S

  
  LOG IN TO REPLY
phigment
THREAD ­ STARTER
Member
230 posts
Likes: 2
Joined Jan 2009
Location: Waterloo, Ontario, Canada
     
May 12, 2009 19:10 |  #20

AlanU wrote in post #7909267 (external link)
Have you tried tweeking with AF micro adjust?

Thanks for the suggestion, but AF seems pretty good now with micro adjust set to zero. Gentec appears to have fixed the front focus issue.

The only difference between those two shots was the aperture. I did not re-focus between shots (use * as AF button).


A7R, Firin 20mm, CV 21/4, CV 40/1.4, 100ZE, 300 4LIS, Tamron 150-600, Jupiter 8, RX100 IV

  
  LOG IN TO REPLY
phigment
THREAD ­ STARTER
Member
230 posts
Likes: 2
Joined Jan 2009
Location: Waterloo, Ontario, Canada
     
May 13, 2009 10:07 |  #21

phigment wrote in post #7909206 (external link)
I have a quick question though. When stopping down the aperture, is the focal distance expected to change? That's exactly what I am seeing.

Once again, searching the net has revealed an answer. This is a classic case of 'focus shift'. I have heard this term before, but did not know what it meant. And I have only seen the term used when reading about the Canon 50L.

I'm curious as to why I never came across it while reading up on the Sigma? Ah well, maybe I just wasn't paying attention to it.


A7R, Firin 20mm, CV 21/4, CV 40/1.4, 100ZE, 300 4LIS, Tamron 150-600, Jupiter 8, RX100 IV

  
  LOG IN TO REPLY
thatkatmat
Cream of the Crop
Avatar
9,340 posts
Gallery: 41 photos
Likes: 199
Joined Jul 2007
Location: Seattle, don't move here, it's wet and cold
     
May 13, 2009 10:16 |  #22

phigment wrote in post #7909284 (external link)
Thanks for the suggestion, but AF seems pretty good now with micro adjust set to zero. Gentec appears to have fixed the front focus issue.

The only difference between those two shots was the aperture. I did not re-focus between shots (use * as AF button).

Perhaps you moved the body while changing the aperture, who knows.
The reason I own an EX50 is because I owned 3-50L's they all shift, makes my type of shooting style near impossible 50% of the time.
There is no focus shift with my Sigma that I can detect, that's one of the reasons I love it, I can shoot at MFD at 1.4 all the way through f4 with no shift, same thing at infinity.


My Flickr (external link)
Stuff
"Never rat on your friends and always keep your mouth shut." -Jimmy Conway
a9, 12-24/4G, 24-70/2.8GM, 100-400GM, 25/2 Batis, 55/1.8ZA, 85 /1.8FE, 85LmkII, 135L...a6300,10-18/4, 16-50PZ, 18-105PZ

  
  LOG IN TO REPLY
phigment
THREAD ­ STARTER
Member
230 posts
Likes: 2
Joined Jan 2009
Location: Waterloo, Ontario, Canada
     
May 13, 2009 10:19 |  #23

thatkatmat wrote in post #7913284 (external link)
Perhaps you moved the body while changing the aperture, who knows.
The reason I own an EX50 is because I owned 3-50L's they all shift, makes my type of shooting style near impossible 50% of the time.
There is no focus shift with my Sigma that I can detect, that's one of the reasons I love it, I can shoot at MFD at 1.4 all the way through f4 with no shift, same thing with infinity.

Camera was on a tripod and it was merely a turn of the dial to adjust the aperture. I highly doubt the camera moved. I was able to reproduce this, going back and forth between 1.4 and 3.2 a few times, just to be sure.

Sigh.. back to Gentec again?


A7R, Firin 20mm, CV 21/4, CV 40/1.4, 100ZE, 300 4LIS, Tamron 150-600, Jupiter 8, RX100 IV

  
  LOG IN TO REPLY
AngryCorgi
-Bouncing Boy- a POTN peion
Avatar
11,543 posts
Likes: 2
Joined Aug 2005
Location: Surrounded by bunnies, squirrels and a couple of crazy corgis in NoVA...
     
May 13, 2009 10:31 |  #24

Your new samples are pretty good actually. Yes, the Sigmalux focus-shifts as most fast-50s do. The low-contrast of the f/1.4 image is normal for good samples of this lens, especially on a high-density sensor such as the 5D2. I have found that for good contrast, f/1.8-f/2 is the range where you see the biggest jump. IOW, you shouldn't need to take it all the way to f/3.2 to make the images really "pop". You can also apply a small amount of USM on the f/1.4 shots to make them sparkle at 100% too.


AngryCorgi (external link) (aka Tom) ...Tools...

...Knowledge is knowing that a tomato is a fruit, Wisdom is knowing not to include it in a fruit salad...

  
  LOG IN TO REPLY
[Hyuni]
Goldmember
Avatar
1,186 posts
Likes: 15
Joined Dec 2008
Location: CHiCAGO
     
May 13, 2009 10:41 |  #25

I think I'm going to send in my siggy to get it calibrated after I get a 17-40L
I didn't really notice a ton of front focusing nor mind it, but a fellow noink user was handling my set up and told me it had front focusing issues and suggested I send it in.
What the process of sending it in for calibration? Do I have to call a number or email them?

Eh~ might as well send it in for a week or two to make it perfect.


6D Rokinon 14 f/2.8 l EF 35 ƒ1.4L l EF 135 ƒ2.0L l EF 70-200 ƒ2.8L IS II l YN460 l 580EX II l Flick'd (external link)

  
  LOG IN TO REPLY
Mr. ­ Clean
Cream of the Crop
Avatar
6,002 posts
Likes: 3
Joined Jul 2005
Location: Olympia, Washington
     
May 13, 2009 10:45 |  #26

Sigma's website has the info under the "support" link.


Mike
some shots @ Zenfolio (external link)
Gear List

  
  LOG IN TO REPLY
wimg
Cream of the Crop
Avatar
6,653 posts
Likes: 30
Joined Jan 2007
Location: Netherlands, EU
     
May 13, 2009 11:04 |  #27

phigment wrote in post #7913231 (external link)
Once again, searching the net has revealed an answer. This is a classic case of 'focus shift'. I have heard this term before, but did not know what it meant. And I have only seen the term used when reading about the Canon 50L.

I'm curious as to why I never came across it while reading up on the Sigma? Ah well, maybe I just wasn't paying attention to it.

I've mentioneed this a few times here on POTN. I tested two different copies of the Sigma 50 F/1.4, and both copies had focus shift. Fine at F/1.4, and at F/2 focus shift was worst, around 1 cm backfocus at a distance of 50 cm, i.e., the focused area was shifted well past the original DoF zone. Focus shift may vary from copy to copy, as with the 50Ls that show the problem. With the copies of teh Sigma I tested at F/4 it was completely gone.

When you read the test on DPReview, you'll find a veiled reference to focus shift, although I don't think the tester really understood what this was about.

Kind regards, Wim


EOS R & EOS 5 (analog) with a gaggle of primes & 2 zooms, OM-D E-M1 Mk II & Pen-F with 10 primes, 6 zooms, 3 Metabones adapters/speedboosters​, and an accessory plague

  
  LOG IN TO REPLY
phigment
THREAD ­ STARTER
Member
230 posts
Likes: 2
Joined Jan 2009
Location: Waterloo, Ontario, Canada
     
May 13, 2009 11:31 |  #28

wimg wrote in post #7913582 (external link)
I've mentioneed this a few times here on POTN. I tested two different copies of the Sigma 50 F/1.4, and both copies had focus shift. Fine at F/1.4, and at F/2 focus shift was worst, around 1 cm backfocus at a distance of 50 cm, i.e., the focused area was shifted well past the original DoF zone. Focus shift may vary from copy to copy, as with the 50Ls that show the problem. With the copies of teh Sigma I tested at F/4 it was completely gone.

When you read the test on DPReview, you'll find a veiled reference to focus shift, although I don't think the tester really understood what this was about.

Kind regards, Wim

Interesting. I didn't actually compare the shift distance with other apertures. Maybe I'll do that tonight, but really, I'm a little sick of testing this out. Time to take some real pictures. :D

Overall, I'm happy with the lens, and the pictures it can take are beautiful. I haven't even noticed the problem (after getting it back from calibration) with everyday shooting.


A7R, Firin 20mm, CV 21/4, CV 40/1.4, 100ZE, 300 4LIS, Tamron 150-600, Jupiter 8, RX100 IV

  
  LOG IN TO REPLY
weezerfan84
Senior Member
Avatar
903 posts
Joined Nov 2008
Location: Fort Smith, AR
     
May 13, 2009 11:34 |  #29

Most problems you notice is only through rigourous testing. I think if more people took pictures instead of testing, than they would enjoy their lens purchases a whole lot more.


Canon 5D classic/Canon 85 1.8/17-40L/Siggy 50 f/1.4 ex/430ex speedlite/and some books

My slowly improving flickr (external link)
https://photography-on-the.net/forum/showthre​ad.php?t=735845

  
  LOG IN TO REPLY
AngryCorgi
-Bouncing Boy- a POTN peion
Avatar
11,543 posts
Likes: 2
Joined Aug 2005
Location: Surrounded by bunnies, squirrels and a couple of crazy corgis in NoVA...
     
May 13, 2009 12:20 |  #30

wimg wrote in post #7913582 (external link)
I've mentioneed this a few times here on POTN. I tested two different copies of the Sigma 50 F/1.4, and both copies had focus shift. Fine at F/1.4, and at F/2 focus shift was worst, around 1 cm backfocus at a distance of 50 cm, i.e., the focused area was shifted well past the original DoF zone. Focus shift may vary from copy to copy, as with the 50Ls that show the problem. With the copies of teh Sigma I tested at F/4 it was completely gone.

When you read the test on DPReview, you'll find a veiled reference to focus shift, although I don't think the tester really understood what this was about.

Kind regards, Wim

Actually, in Markus' review of the Nikon 50/1.4G on Photozone, he mentions the focus shift issue (and its comparable to the Sigma), so I'm sure he is familiar with the issue. I'm pretty sure Klaus is also familiar with focus shift --- he must have just failed to make a big deal about it in the Sigma review.


AngryCorgi (external link) (aka Tom) ...Tools...

...Knowledge is knowing that a tomato is a fruit, Wisdom is knowing not to include it in a fruit salad...

  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)

5,443 views & 0 likes for this thread
Soft Sigma 50mm 1.4 HSM
FORUMS Canon Cameras, Lenses & Accessories Canon EF and EF-S Lenses 
AAA
x 1600
y 1600

Jump to forum...   •  Rules   •  Index   •  New posts   •  RTAT   •  'Best of'   •  Gallery   •  Gear   •  Reviews   •  Member list   •  Polls   •  Image rules   •  Search   •  Password reset

Not a member yet?
Register to forums
Registered members may log in to forums and access all the features: full search, image upload, follow forums, own gear list and ratings, likes, more forums, private messaging, thread follow, notifications, own gallery, all settings, view hosted photos, own reviews, see more and do more... and all is free. Don't be a stranger - register now and start posting!


COOKIES DISCLAIMER: This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies and to our privacy policy.
Privacy policy and cookie usage info.


POWERED BY AMASS forum software 2.1forum software
version 2.1 /
code and design
by Pekka Saarinen ©
for photography-on-the.net

Latest registered member is sageybadegey
1061 guests, 320 members online
Simultaneous users record so far is 15144, that happened on Nov 22, 2018

Photography-on-the.net Digital Photography Forums is the website for photographers and all who love great photos, camera and post processing techniques, gear talk, discussion and sharing. Professionals, hobbyists, newbies and those who don't even own a camera -- all are welcome regardless of skill, favourite brand, gear, gender or age. Registering and usage is free.