GH2 with Olympus Zuiko 14-35 : Autofocus problem

But one question is bothering me now: Why is there no AF with the GH1 using the Zuiko 14-35mm?

Same conectors and adapters as with the GH2. So, its only software related. And the protocoll is long known before the GH1 was on the market. Is it just unabled in the GH1 to give all people with expensive glass a "good" reason to buy the GH2. Is it just again to make more money...

Lets think about it:
- the AF function is located in the GH1 body (it doesn't need any metering from the lens)
- the camera is able to controll the AF motor (as you can see when switching the camera off, the lens will be driven to focus at infinity)


Is there anything in the firmware that looks like a list of device IDs and on/off flags to it? (Most of the flags would be set to "off" according to the list postet above).
 
I have the 14-35 on a GH2 with the Panasonic adapter...

Has anyone else with this combo noticed the lens changing F-stop?

When (at F2.0) I zoom all the way out, right before I reach 14mm the lighting all of a sudden gets darker, at the same moment I can hear the lens make the F-stop change.

If I set the lens to F2.2 this does not happen and the F-stop remains constant.



- updating the firmware was no problem.

- focus is very slow but I shoot manual
 
SPScheibel said:
When (at F2.0) I zoom all the way out, right before I reach 14mm the lighting all of a sudden gets darker, at the same moment I can hear the lens make the F-stop change.

If I set the lens to F2.2 this does not happen and the F-stop remains constant.
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This is a recurring design flaw in Olympus and Panasonic electronic iris lenses. The lens firmware is designed to dynamically adjust the iris to simulate a constant f-stop as the lens is zoomed. It will also alter the f-stop on lenses whose widest aperture is non-constant. However, it doesn't desist with this f-stop readjustment until you select an f-stop one click beyond the widest constant aperture. The same thing happens on my Panasonic 14-50mm f2.8-3.5 lens, and it's annoying to have to set it to no wider than F4 to zoom freely with it.
 
lpowell said:
This is a recurring design flaw in Olympus and Panasonic electronic iris lenses. The lens firmware is designed to dynamically adjust the iris to simulate a constant f-stop as the lens is zoomed. It will also alter the f-stop on lenses whose widest aperture is non-constant. However, it doesn't desist with this f-stop readjustment until you select an f-stop one click beyond the widest constant aperture. The same thing happens on my Panasonic 14-50mm f2.8-3.5 lens, and it's annoying to have to set it to no wider than F4 to zoom freely with it.
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I 100% understand having to set a variable f2.8-3.5 lens higher than 3.5 to avoid the change in f-stop.

Please correct me if I'm wrong but this Zuiko 14-35 2.0 lens is promoted and sold with specs as being a constant f-stop... regardless of the zoom. Not simulated in any way... the lens should always remain at the F-stop I set. These are part the specs that make this lens so amazing/expensive.

Please don't tell me there is a top of the line $2300.00 lens on the market that is not doing what it says it does, and we know this, and we're ok with it? This can't be true.
 
SPScheibel said:
Please don't tell me there is a top of the line $2300.00 lens on the market that is not doing what it says it does, and we know this, and we're ok with it? This can't be true.
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I'd be perfectly ok with it if Panasonic would only take my sage advice, buy Olympus Corporation outright, and release native Micro 4/3 versions of the high-end Zuiko lenses with full auto-focus support across the entire G-series and AF100 lines.

But as for the 14-35mm's "constant" f-stop, the lens doesn't actually have a mechanical mechanism that maintains a constant f-stop while zooming. Reason being, the iris must open wider as the focal length decreases, in order to maintain the same f-number. In an electronic iris lens, the iris is dynamically adjusted by the firmware to simulate the effect of a constant f-stop. Ideally, this would be done continuously and steplessly, and there would be no visible variation in exposure while zooming.
 
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So am I to understand that everyone who purchases this lens (priced at more than $2000) expecting to get a constant F-stop, is actually not getting a constant F-stop? Are you saying this lens does not perform as specified by the manufacturer?

Why is no one else reporting any issue with this? This just doesn't seem real!
 
Well, the lens' f-stop is technically constant, it's the T-stop that isn't quite seamless in all zooming maneuvers. And since these are lenses designed for still photography rather than cinematography, one wouldn't expect Olympus to document or guarantee their T-stop behavior.
 
Some seem to be forgetting that the 35-100 (and 14-35) are STILL lenses. They do exactly what they claim to do when used to shoot stills. It's really not Olympus's fault/problem that people have bought these lenses for use in video. I own both, use them almost exclusively for video, and absolutely love them. Then again, I don't expect them to do anything they weren't designed to do.

[Pretty much what lpowell said - should have read his whole post :) ]
 
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This is not a showstopper. What's the chance that one zooms out all the way to 14mm while recording? If it is, set it to 2.2.

I sure hope Oly releases m43 versions.
 
This just seems a little weird guys... I want to make it perfectly clear that I really love the picture I am getting from the lens!

My simple question is this - For the people who own and use the GH1 or GH2, with the Panasonic adapter, and the Olympus 14-35 2.0... While in manual mode, with the lens set to f2.0, do you see the lighting change when zoomed all the way out?
 
stonebat said:
I don't own the lens. But did you secure it on a rig? If yes, how did you support the lens? Thanks.
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The lens is fine on my GH2 without any support, and I have not put it all in a rig either. When attached to the GH2 I generally end up holding the lens, as it is about twice as heavy as the camera, but that is not a complaint - it feels great.
 
I wouldn't put this lens on a rig without supporting it at the front end - its quite heavy and the adapter making it even longer, the torque on the mount can destort the camera body.

But there is an extra metall ring in the plastic housing of the lens near the front end - perfectly suitable for a lens support. Just get a big enough bracket with some rubber on it to hold the lens.

I will make one my self for my rig (also DIY) - but there should be something suitable to buy out there ;-)
 
See this thread I started a while back in the AF100 forum.
http://www.dvxuser.com/V6/showthread.php?234515-Olympus-14-35-35-100-zoom-lens-owners

SPScheibel said:
So am I to understand that everyone who purchases this lens (priced at more than $2000) expecting to get a constant F-stop, is actually not getting a constant F-stop? Are you saying this lens does not perform as specified by the manufacturer?

Why is no one else reporting any issue with this? This just doesn't seem real!
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