Camera Labs

Very interesting question and great thread.

Well done Popo. Theory is all nice and interesting but in the end the proof of the pudding is in the empirical data. If that lens takes 8 frames or 8/60 of a second to go through a single close-open cycle then on a 10 fps camera it would need 80/60 of a second to do so for those 10 shots. That's 20/60 more than there are in a second so this might indeed be an interesting problem.

More tests would seem useful.

Ben
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When in doubt..... Press the shutter.

Interesting read guys, keep the info coming! Good work on the tests popo!

- Bjorn -

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Street and documentary photographer | Google+ | Twitter | Blog | Tumblr

Leica M9-P (my article on Camera Labs) | Leica D-Lux 5 | 50mm Summilux

Hi popo,

Thanks for taking the time and trouble and congratulations on producing a superb post.

Update: After a little time to reflect I was actually surprised that the iris movement of the Canon 50mm f/1.8 was so slow. But it's probably worth remembering that Canon's AF is rated down to f/5.6 on the 7D so for the lens tested I don't see the iris performance opening all the way up to f/1.8 as being limiting when using AF tracking at 8 or 10fps, but that's just a guess. But, of course, this thread isn't Canon specific and I think the result of the test above is sufficiently close to justify asking the original question. I hope Gordon manages to coax some definitive statements from his contacts in due course.


Bob.

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OM-D E-M5 + ED 12-50mm, H-PS14042E, H-F007014E, L-RS014150E, M.ZUIKO DIGITAL 45mm 1:1.8.
Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.

Interesting idea, that is testable although I'm not sure I'm motivated to set up again to try it.

I should also point out a weakness in my earlier test. That was with the camera in single shot mode, where it would know it does not need to be in a particular hurry to finish a cycle. It may act differently in other modes.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.

Isn't the iris mechanically operated by the camera body? Any speed improvements can then be made to the body to match the the frame rate and AF speed of the camera. No?

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Graham
Flickr

Hi Graham,

Not with Canon's EF/EF-S lenses. Is the iris on Nikkor lenses controlled mechanically from the camera body? And I wonder what the arrangement is for the other players such as Pentax, Sony etc.?

Bob.

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OM-D E-M5 + ED 12-50mm, H-PS14042E, H-F007014E, L-RS014150E, M.ZUIKO DIGITAL 45mm 1:1.8.
Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.

Sony's using the body to control the aperture. Nikon too, from what I've seen in YouTube videos.

- Bjorn -

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Street and documentary photographer | Google+ | Twitter | Blog | Tumblr

Leica M9-P (my article on Camera Labs) | Leica D-Lux 5 | 50mm Summilux

Yes, the Nikkors are controlled from the body, I just never thought that it would be any other way.

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Graham
Flickr

Hi folks,

I thought I'd resurrect this thread as, from Gordon's Sony Alpha SLT-A77 preview, it would appear that, at least so far as Sony is concerned, the answer is less than 12 fps.

Bob.

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OM-D E-M5 + ED 12-50mm, H-PS14042E, H-F007014E, L-RS014150E, M.ZUIKO DIGITAL 45mm 1:1.8.
Gitzo GT1541T, Arca-Swiss Z1 DP ball-head.
Astrophotography: TEC 140 'scope, FLI ML16803 camera, ASA DDM60 Pro mount.

Good work popo, interesting topic.

This makes me think about lenses in general, they have mechanical components. Do they wear out?
Does IS, VR, OS and the focus drives like USM have a definitive life?
Do lenses deteriorate?

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Canon Powershot S95, Canon 7D, 15-85, Canon 85 1.8 USM, Sigma 30 1.4, 50mm 1.8, Canon 100 2.8L IS Macro, Canon 70-300L IS USM+Kenko 1.4 Pro 300DGX, Canon 430EX II and RS 4 Classic

Bob, I was told (a long time ago) that the reason that A-mount cameras couldn't go faster than 5.5 fps, was the aperture. Apparently this isn't a problem at all anymore (or it just wasn't the case ), as last year's A55 can do 6 fps with full metering and autofocus, and the A77 announced last month can do that as well, but at 8 fps...

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Sony α77V/VG-C77AM/α350/18-70/70-400 G SSM/NEX-5/18-55 OSS/Lowepro Pro Trekker 600 AW/CompuTrekker AW/Nova 140 AW/Street & Field gear/Toploader Pro 75 AW. And a huge wishlist...

My photos on Flickr...

Hi Bob, I'm glad you resurrected this thread in the light of the Sony A77, which as you pointed out, can only achieve its top speed of 12fps if the lens iris is kept fixed (falling to 8fps for variable aperture control). I wonder if Canon is already close to or even at the physical / traditional limit with the 10fps of the 1D Mark IV?

I think we may see some electronic shutters implemented for faster speeds in the future. Or high resolution video. Or a mix of the two...

Well, Canon has the "youngest" lens mount out of the leading brands? Then again Nikon still uses the mechanical lever.

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I take pictures so quickly, my highschool was "Continuous High".

I'm no expert, but wouldn't the iris stayed fixed in a high-speed burst? It'd obviously be open while focusing/metering, but once that shutter button is fully depressed, I think the iris would stay in its closed position until you were done. (If AI/servo mode works during a continuous burst, then I'd be wrong.)

Edit: Thinking about, I guess it'd have to open and shut because it'd be pretty dim in continuous burst if it didn't. Then again, i never tried continuous burst with F22 before.