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jun
Joined: 25 Jan 2011
Posts: 54
Location: Philippines
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 Posted: Sat Jun 11, 2011 10:48 am Post subject: infinity focus?move lens away or nearer |
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jun wrote:
i can't seem to achieve infinity focus on my lens. maybe it is because of nex canon adapter.
just wanted to know if you can't achieve infinity focus does it mean your lens is too near or far from the film plane?
or in order to achieve infinity focus do i move the lens away from the body (add a couple of fillers) or move the lens towards the body (shaving the adapter)
thanks
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mc rokkor 58 f1.4, mc rokkor 135 f2.8, canon fd 50 f1.4, yashica ml 50 f1.9, sigma 80-200 f4, tokina 80-200 f4, sony nex 16mm f2.8, sony alpha 18-70 f3.5-5.6, pentax smc f 35-70mm f3.5-5.6, canon efs 18-55 f3.5-5.6, tokina 28 f2.8, canon fl 58 f1.2 |
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fuzzywuzzy
Joined: 18 Dec 2010
Posts: 1258
Location: Down East, Canada, eh?
Expire: 2013-11-30
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| Posted: Sat Jun 11, 2011 11:18 am Post subject: |
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fuzzywuzzy wrote:
Unfortunately infinity is achieved by getting closer to the sensor (film).
The other way allows you to focus closer, i.e. extension tubes can turn a regular lens into a close-focus macro lens.
Probably not what you wanted to hear  |
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poilu
Joined: 26 Aug 2007
Posts: 10471
Location: Greece
Expire: 2019-08-29
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| Posted: Sat Jun 11, 2011 11:24 am Post subject: |
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poilu wrote:
most lenses can be tuned, search if it is possible with yours
http://forum.mflenses.com/infinity-tune-for-contax-lens-t7011.html
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jun
Joined: 25 Jan 2011
Posts: 54
Location: Philippines
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| Posted: Sat Jun 11, 2011 12:59 pm Post subject: thanks |
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jun wrote:
the extension tube principle. so it means my adapter is too thick?
thanks guys.
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mc rokkor 58 f1.4, mc rokkor 135 f2.8, canon fd 50 f1.4, yashica ml 50 f1.9, sigma 80-200 f4, tokina 80-200 f4, sony nex 16mm f2.8, sony alpha 18-70 f3.5-5.6, pentax smc f 35-70mm f3.5-5.6, canon efs 18-55 f3.5-5.6, tokina 28 f2.8, canon fl 58 f1.2 |
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David
Joined: 13 Apr 2011
Posts: 1869
Location: Denver, Colorado
Expire: 2013-01-25
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| Posted: Sat Jun 11, 2011 8:25 pm Post subject: |
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David wrote:
I had a similar issues on flanged adapters for my M42 lenses and my K07 DSLR. The unflanged ones allow infinity focus. So, the principle and issue is likely the same: the adapter changes the flange focal distance by pushing the rear element away from the sensor. This sacrifices the lens' ability to infinity focus as a tradeoff for using it on different cameras.
some lenses and adapters work well, for instance M42 to Pentax K because the flange focal distance in the same (Pentax specifically designed their bayonet mount for adapter creation to allow M42 lenses to be used to their full ability.) However, I could not use an M39 lens on my K-7 because the flange focal distance on an M39 lens is something like 18mm (vs. 45.46mm on the K mount and M42.) The result would be the lens focus being off by the difference in flange focal distance, and having a substantially limited focal range that increases in-kind with the adapter's thickness.
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RioRico
Joined: 12 Mar 2010
Posts: 1120
Location: California or Guatemala or somewhere
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| Posted: Tue Jun 14, 2011 1:51 pm Post subject: |
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RioRico wrote:
| David wrote: |
| I could not use an M39 lens on my K-7 because the flange focal distance on an M39 lens is something like 18mm (vs. 45.46mm on the K mount and M42.) |
Actually, M39 register (Flange focal distance) is the same as M42. I use several M39 lenses on my Pentax K20D and achieve infinity focus. The L39 / LTM (Leica threadmount) register is 28.8mm. Such can only be adapted to Pentax for non-macro use by performing radical surgery. And AFAIK the only mount with 18mm register is Sony NEX.
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Too many film+digi cams+lenses, oh my -- Pentax K20D, K-1000, M42s, more
The simple truth is this: There are no neutral photographs. --F-Stop Fitzgerald |
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