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jamaeolus
Joined: 19 Mar 2014
Posts: 2927
Location: Eugene
Expire: 2015-08-20
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 Posted: Wed Jun 22, 2022 8:27 pm Post subject: reverse lens FL inquiry. |
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jamaeolus wrote:
I purchased a Schneider Componon S 180mm 5.6 to play around with and the only way I could mount it right away was reversed. I have ordered an adapter to fit the correct way but in the meantime I am using it reversed. My Sony a7Rii has steady shot which wants a FL input for the lens. Anybody know what the FL is in the reversed oreintation? Or how to calculate it?
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Gerald
Joined: 25 Mar 2014
Posts: 1196
Location: Brazil
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| Posted: Wed Jun 22, 2022 9:14 pm Post subject: |
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Gerald wrote:
The FL is the same, no matter the orientation!
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If raindrops were perfect lenses, the rainbow did not exist. |
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visualopsins
Joined: 05 Mar 2009
Posts: 10531
Location: California
Expire: 2025-04-11
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| Posted: Thu Jun 23, 2022 1:21 am Post subject: |
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visualopsins wrote:
| jamaeolus wrote: |
| My Sony a7Rii has steady shot which wants a FL input for the lens. |
For closer higher magnifications, steady shot setting should be increased imho.
| Gerald wrote: |
| The FL is the same, no matter the orientation! |
Quite true!  However, back focus can and often does change, hence the difference is focus distances.
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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 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 (Kiron)
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RokkorDoctor
Joined: 27 Nov 2021
Posts: 1267
Location: Kent, UK
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| Posted: Thu Jun 23, 2022 8:42 am Post subject: Re: reverse lens FL inquiry. |
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RokkorDoctor wrote:
| jamaeolus wrote: |
| I purchased a Schneider Componon S 180mm 5.6 to play around with and the only way I could mount it right away was reversed. I have ordered an adapter to fit the correct way but in the meantime I am using it reversed. My Sony a7Rii has steady shot which wants a FL input for the lens. Anybody know what the FL is in the reversed oreintation? Or how to calculate it? |
With a digital body like the A7Rii you don't have to worry about film cost, so I would suggest to experiment and try which FL works best at the magnification you are using the lens.
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Mark
SONY A7S, A7RII + dust-sealed modded Novoflex/Fotodiox/Rayqual MD-NEX adapters
Minolta SR-1, SRT-101/303, XD7/XD11, XGM, X700
Bronica SQAi
Ricoh GX100
Minolta majority of all Rokkor SR/AR/MC/MD models made
Sigma 14mm/3.5 for SR mount
Tamron SP 60B 300mm/2.8 (Adaptall)
Samyang T-S 24mm/3.5 (Nikon mount, DIY converted to SR mount)
Schneider-Kreuznach PC-Super-Angulon 28mm/2.8 (SR mount)
Bronica PS 35/40/50/65/80/110/135/150/180/200/250mm |
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Gerald
Joined: 25 Mar 2014
Posts: 1196
Location: Brazil
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| Posted: Thu Jun 23, 2022 1:58 pm Post subject: |
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Gerald wrote:
| visualopsins wrote: |
| Gerald wrote: |
| The FL is the same, no matter the orientation! |
Quite true! However, back focus can and often does change, hence the difference is focus distances. |
For macro photography an IS system needs to be a 5-axis IBIS type to be effective. With a native lens, in addition to the information sent by the sensors (Yaw, Pitch, Roll, X and Y), the camera's computer knows the focal length AND focus distance. That is, the camera's computer has all the information it needs to do an excellent job of image stabilization.
Things get a little more complicated with an adapted lens. The photographer can manually enter the focal length, but not the focus distance. So, I believe that with adapted lenses, the IS system of existing cameras drops to 3-axis image stabilization mode, which works great for infinity shots, but not so well for macro photography.
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If raindrops were perfect lenses, the rainbow did not exist. |
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