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dbuergi
Joined: 30 Sep 2015 Posts: 102 Location: Germany
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Posted: Thu Jan 24, 2019 9:55 am Post subject: SMC Pentax 28mm 3.5 not reaching infinity focus |
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dbuergi wrote:
Hi,
yesterday i tried to make some test shots with my Pentax 28mm on a Sony A7. On short distance and up to 2m everything is fine. When i tried to make a pic at infinity the sharpness stops at around 3m.
The focus ring shows infinity and so i think that the lens needs an infinity focus adjustment. Does anybody have pics or a DIY plan how this can be done or should i try to find a repair shop for this task? _________________ Follow me on Instagram @danyelbfoto
Visit my youtube channel about watches and photography:
https://www.youtube.com/channel/UCTovFaSeg8Gsvz-h9U8Fo4g/ |
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VLR
Joined: 05 Mar 2015 Posts: 86
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Posted: Thu Jan 24, 2019 4:32 pm Post subject: |
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VLR wrote:
It could be that the lens needs adjustment. But it could also be the adapter - if it's too thick, you won't reach infinity focus. This problem will be more pronounced the wider the lens. Did you use any other lens on the adapter to check?
In any case, more specific info on the lens (max. aperture, full name) would be helpful! _________________ http://vintagelensreviews.com/
Reviews of vintage Minolta SR mount lenses and more |
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DConvert
Joined: 12 Jun 2010 Posts: 901 Location: Essex UK
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Posted: Thu Jan 24, 2019 4:41 pm Post subject: |
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DConvert wrote:
Adapter issues are quite common but would normally ensure focus beyond infinity.
If you have access to a micrometer or measuring callipers the adapter is easy to check out. It should be 27.46mm from the rear plate that mounts on the camera to the front plate the lens mounts on. |
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Gardener
Joined: 22 Sep 2013 Posts: 950 Location: USA
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Posted: Sat Jan 26, 2019 3:08 pm Post subject: |
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Gardener wrote:
With glass like that the first move should be putting it on a native body. |
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visualopsins
Joined: 05 Mar 2009 Posts: 10462 Location: California
Expire: 2021-06-22
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Posted: Sat Jan 26, 2019 10:03 pm Post subject: |
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visualopsins wrote:
Gardener wrote: |
With glass like that the first move should be putting it on a native body. |
Maybe for you... VLR has asked if the adapter has been used successfully with another lens. If yes what use is putting on native body? _________________ ☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮ like attracts like! ☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮
Cameras: Sony A7Rii, Spotmatics II, F, and ESII, Nikon P4
M42 Asahi Optical Co., Lenses:
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
Other lenses:
Carl Zeiss Jena Flektogon 2.4/35
SMC PENTAX 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 (51BB), SP 500mm f/8 (55BB), SP 70-210mm f/3.5 (19AH)
Vivitar 100mm 1:2.8 MC 1:1 Macro Telephoto
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DConvert
Joined: 12 Jun 2010 Posts: 901 Location: Essex UK
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Posted: Mon Jan 28, 2019 9:13 am Post subject: |
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DConvert wrote:
visualopsins wrote: |
Gardener wrote: |
With glass like that the first move should be putting it on a native body. |
Maybe for you... VLR has asked if the adapter has been used successfully with another lens. If yes what use is putting on native body? |
If the other lens has a longer focal length any issues with the adapter will be reduced. So just testing the adapter with another lens isn't necessarily informative. (Sometimes adapters can be modified for faulty lenses too - but I'd expect that to be pretty unusual) |
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visualopsins
Joined: 05 Mar 2009 Posts: 10462 Location: California
Expire: 2021-06-22
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Posted: Mon Jan 28, 2019 5:41 pm Post subject: |
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visualopsins wrote:
DConvert wrote: |
visualopsins wrote: |
Gardener wrote: |
With glass like that the first move should be putting it on a native body. |
Maybe for you... VLR has asked if the adapter has been used successfully with another lens. If yes what use is putting on native body? |
If the other lens has a longer focal length any issues with the adapter will be reduced. So just testing the adapter with another lens isn't necessarily informative. (Sometimes adapters can be modified for faulty lenses too - but I'd expect that to be pretty unusual) |
True, however with 28mm only focusing to 3m, an adapter error would be large enough to affect 50mm lens and likely 135mm lens, which are probably the most common other lenses tried, if any. _________________ ☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮ like attracts like! ☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮☮
Cameras: Sony A7Rii, Spotmatics II, F, and ESII, Nikon P4
M42 Asahi Optical Co., Lenses:
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
Other lenses:
Carl Zeiss Jena Flektogon 2.4/35
SMC PENTAX 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 (51BB), SP 500mm f/8 (55BB), SP 70-210mm f/3.5 (19AH)
Vivitar 100mm 1:2.8 MC 1:1 Macro Telephoto
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Eberbach
Joined: 25 Aug 2017 Posts: 1
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Posted: Tue Jan 29, 2019 7:56 am Post subject: |
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Eberbach wrote:
This page may help you. Sorry it's written in Japanese.
[ gryffine.blog100.fc2.com/blog-entry-6.html ]
See the fourth pic.
Loosen three screws beside lens unit.
Next slightly turn a focus ring and tighten the screws.
Test infinity. |
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