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Nikos
Joined: 17 May 2010
Posts: 1077
Location: Greece
Expire: 2015-01-02
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 Posted: Fri Dec 03, 2010 10:44 pm Post subject: Zeiss 21mm ZE/ZF: Bad focusing scale? |
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Nikos wrote:
I have an issue with my Zeiss 2,8/21 ZE:
If I use the hyperfocal distance indicated on the lens, objects at infinity come out way too blurred.
For f/8, the HF indicated on the lens is roughly 2m. However, this produces blurred infinity even at f/10.
What is interesting, the focus throw between 2m and infinity is roughly equal to the throw
between 1m and 2m. I think this is weird for an ultra wide lens.
I suspect the focus scale on the lens is not accurate at all.
So, what I do is to focus the lens at infinity. Then, using f/8, anything from about 2m up to infinity is tack sharp.
Do we have other owners of this lens here?
What is the case with old 21mm Distagon?
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Cameras: Canon EOS 5D Mark II, Sony α7R, Sony NEX-5N
MF lenses:
SLR:
Canon TS-E 17mm f/4, Zeiss 2.8/21 ZE, Zeiss 2/28 Contax, Zeiss 2/35 ZE, Zeiss 1.4/50 Contax, Zeiss 1.4/85 Contax, Zeiss Makro 2/100 ZE,
Zeiss 2/135 Contax, Zeiss 2.8/135 Contax, Zeiss Vario-Sonnar 35-70 Contax, Zeiss Vario-Sonnar 100-300 Contax, Zeiss F-Distagon Rollei, Canon FD 24mm f2, Minolta MD Rokkor 35mm f2.8
Rangefinder:
Zeiss 4.5/21 C Biogon ZM, Zeiss 2/35 Biogon ZM, Voigtländer 15mm f/4.5 Heliar L39, Leica Tele-Elmarit 2.8/90mm, Zeiss 2/45 Contax G, Zeiss 2.8/90 Contax G, Canon 50mm 1.8 LTM
AF lenses: Canon 15mm f/2.8 Fisheye, Canon 24-70 f/2.8 L, Canon 70-200 f/2.8 L IS II, Canon 70-200 f/4 L, Canon 300 f/4 L IS, Canon 100 f/2.8 macro
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Orio
Joined: 24 Feb 2007
Posts: 29545
Location: West Emilia
Expire: 2012-12-04
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| Posted: Fri Dec 03, 2010 11:08 pm Post subject: |
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Orio wrote:
Test the lens wide open focusing on infinity using liveview and check if perfect focus is obtained or not, and if yes, where does it fall on the scale.
If the perfect focus is not obtained, or if it is obtained at a point in scale that is not infinity, you need to mail your lens back to Zeiss for servicing.
I have not noticed this problem with the Distagon 21 Contax, but I never use the 21 wide open, so I might have missed any issue (on the other hand, for use on digital with Contax lens, the adapter plays a role also. So the Contax lens should be tested on Contax cameras only).
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Laurentiu Cristofor
Joined: 23 Oct 2010
Posts: 524
Location: WA, USA
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| Posted: Fri Dec 03, 2010 11:13 pm Post subject: |
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Laurentiu Cristofor wrote:
According to an online DOF calculator, their scale appears to be fine: HF is 6.1 feet at f/8 for 21mm with 0.03 CoC value. Maybe the focusing is not calibrated correctly - i.e. when you select 2m, you're actually focusing closer than that?
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Nikos
Joined: 17 May 2010
Posts: 1077
Location: Greece
Expire: 2015-01-02
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| Posted: Fri Dec 03, 2010 11:36 pm Post subject: |
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Nikos wrote:
| Laurentiu Cristofor wrote: |
| According to an online DOF calculator, their scale appears to be fine: HF is 6.1 feet at f/8 for 21mm with 0.03 CoC value. Maybe the focusing is not calibrated correctly - i.e. when you select 2m, you're actually focusing closer than that? |
Yes, the HF values seem to be correct. However my results are not.
I am afraid you guys may be right and I have to send the lens for servicing.
I also have the 2/35 ZE, and I never had this issue, although it is far less wide than the 21mm. |
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visualopsins
Joined: 05 Mar 2009
Posts: 10966
Location: California
Expire: 2025-04-11
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| Posted: Fri Dec 03, 2010 11:39 pm Post subject: |
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visualopsins wrote:
I have noticed similar behavior using wide Takumars. Subject at hyperfocal distance is perfectly in focus, but the coc at infinity are too big for my tastes. When I want infinity in focus I don't use lens hyperfocal settings, but focus farther until infinity looks good. I think hyperfocal settings work best for subjects at close range, within 3 meters, where infinity focus doesn't matter as much as for landscape with foreground to background in focus.
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Cameras: Sony ILCE-7RM2, Spotmatics II, F, and ESII, Nikon P4
Lenses:
M42 Asahi Optical Co., Takumar 1:4 f=35mm, 1:2 f=58mm (Sonnar), 1:2.4 f=58mm (Heliar), 1:2.2 f=55mm (Gaussian), 1:2.8 f=105mm (Model I), 1:2.8/105 (Model II), 1:5.6/200, Tele-Takumar 1:5.6/200, 1:6.3/300, Macro-Takumar 1:4/50, Auto-Takumar 1:2.3 f=35, 1:1.8 f=55mm, 1:2.2 f=55mm, Super-TAKUMAR 1:3.5/28 (fat), 1:2/35 (Fat), 1:1.4/50 (8-element), Super-Multi-Coated Fisheye-TAKUMAR 1:4/17, Super-Multi-Coated TAKUMAR 1:4.5/20, 1:3.5/24, 1:3.5/28, 1:2/35, 1:3.5/35, 1:1.8/85, 1:1.9/85 1:2.8/105, 1:3.5/135, 1:2.5/135 (II), 1:4/150, 1:4/200, 1:4/300, 1:4.5/500, Super-Multi-Coated Macro-TAKUMAR 1:4/50, 1:4/100, Super-Multi-Coated Bellows-TAKUMAR 1:4/100, SMC TAKUMAR 1:1.4/50, 1:1.8/55
M42 Carl Zeiss Jena Flektogon 2.4/35
Contax Carl Zeiss Vario-Sonnar T* 28-70mm F3.5-4.5
Pentax K-mount SMC PENTAX-A ZOOM 1:3.5 35~105mm, SMC PENTAX ZOOM 1:4 45~125mm
Nikon Micro-NIKKOR-P-C Auto 1:3.5 f=55mm, NIKKOR-P Auto 105mm f/2.5 Pre-AI (Sonnar), Micro-NIKKOR 105mm 1:4 AI, NIKKOR AI-S 35-135mm f/3,5-4,5
Tamron SP 17mm f/3.5 (51B), Tamron SP 17mm f/3.5 (151B), SP 500mm f/8 (55BB), SP 70-210mm f/3.5 (19AH)
Vivitar 100mm 1:2.8 MC 1:1 Macro Telephoto (Kiron)
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Nikos
Joined: 17 May 2010
Posts: 1077
Location: Greece
Expire: 2015-01-02
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| Posted: Fri Dec 03, 2010 11:58 pm Post subject: |
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Nikos wrote:
| visualopsins wrote: |
| I have noticed similar behavior using wide Takumars. Subject at hyperfocal distance is perfectly in focus, but the coc at infinity are too big for my tastes. When I want infinity in focus I don't use lens hyperfocal settings, but focus farther until infinity looks good. I think hyperfocal settings work best for subjects at close range, within 3 meters, where infinity focus doesn't matter as much as for landscape with foreground to background in focus. |
I agree that the value typically used for the CoC is outdated for modern digital cameras.
When examining a 21MP photo at 100%, you notice things you would never have noticed in a 20X30 cm print...
Using a value of 0.02 for the Circle of Confusion (instead 0f 0.03), moves the HF point about 1m: from 1.86m to 2.78m.
In this case, even f/11 is not enough to get perfect infinity focus. |
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AhamB
Joined: 22 Jun 2008
Posts: 733
Location: Germany
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| Posted: Sat Dec 04, 2010 3:28 pm Post subject: |
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AhamB wrote:
Basically, you need to make your own table of hyperfocal distances and apertures for your camera+lens combination through empirical testing. In the days of film the hyperfocal indicators worked, but not anymore on digital. |
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Sevo
Joined: 22 Aug 2008
Posts: 1189
Location: Frankfurt, Germany
Expire: 2012-12-03
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| Posted: Sat Dec 04, 2010 3:51 pm Post subject: Re: Zeiss 21mm ZE/ZF: Bad focusing scale? |
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Sevo wrote:
| nkanellopoulos wrote: |
throw between 2m and infinity is roughly equal to the throw
between 1m and 2m.
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That is to be expected on every lens whose helicoid has linear scaling (some CRC and IF lenses and many zooms are non-linear). Halving the distance doubles the extension.
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