Lumix G 20mm F1.7 burst rate mystery

Rihrds said:

Rihrds wrote:

Hello,

While shooting outside on a sunny day with my E-PL5 and Panny 20mm I discovered an upleasant bug(?) - as you close the aperture (and you need to close it in sunny environment), the burst rate drops. It's definitely not 8 fps as soon as you set aperture to F1.8 and gets even slower as you close it more.

Here, I made a video how it looks:

I set the shooting mode to manual to not affect the shutter speed or any other settings.

There is no such problem with other lenses I have. The kit lens and 40-150mm shoots 8 fps at any aperture and I wonder if anyone has an explanation for such Lumix 20mm lens behaviour.

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Guy Parsons said:

Guy Parsons wrote:

Guy Parsons said:

Rihrds wrote:

Hello,

While shooting outside on a sunny day with my E-PL5 and Panny 20mm I discovered an upleasant bug(?) - as you close the aperture (and you need to close it in sunny environment), the burst rate drops. It's definitely not 8 fps as soon as you set aperture to F1.8 and gets even slower as you close it more.

Here, I made a video how it looks:

I set the shooting mode to manual to not affect the shutter speed or any other settings.

There is no such problem with other lenses I have. The kit lens and 40-150mm shoots 8 fps at any aperture and I wonder if anyone has an explanation for such Lumix 20mm lens behaviour.

Click to expand...

My guess is that the larger physical aperture size has a lot further to move to stop down and that takes extra time when compared to the small aperture in the kit lens.

No 20mm here to check but my Sigma 19/2.8 does much the same slow down comparing f/2.8 to f/16 on my E-PL5.

Regards..... Guy

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djbrom said:

djbrom wrote:

This is a known issue that affects older Panny lenses. The 100-300mm panny is also affected. Basically the aperture system on the lens is based on an older design and cannot move fast enough for the burst rate of the new cameras like the EM5. This was acknowledged by Panasonic and I read the article from them. I will try to find it again and post it here. It was primarily for the 100-300mm by memory but any older lens will be affected in the same way.

*edit*

Here is the link

http://fourthirds-user.com/2012/07/fast_frame_rate_problem_with_panasonic_lumix_100300_zoom.php

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photofan1986 said:

photofan1986 wrote:

Same problem here with PL 25 1.4, but not so pronounced. The burst rate slows down as the aperture is closed. My 14 2.5 is even worse at this, and my dad's 20 1.7 is the worst. Its aperture mechanism seems very slow.

However, I tested the Oly 14-42 kit lens, and not only it does not slow down, but I noticed that the aperture is not opened between consecutive shots in high speed burst. In low speed burst, you can see the aperture opens between frames, probably for autofocus.

There is one consequence to all this, besides the slower frame rate. The so-called "rattlesnake", which happens not only with the 25 1.4 (but more noticeable on this lens, because of the big and noisy aperture blades), causes the camera to slow down when shooting, even in single mode. Why? Simply because the lens is already in a "stopped down" position by default during live view, then it has to open wide to make the focus adjustments, and then again stop down to the selected value. And this operation takes quite a while. I can definitely feel a difference in shutter lag when the camera enters the "rattlesnake mode" (to compensate for light flicker for example).

It's a shame and I find it very annoying. The EPM2 I had for a couple of days had an option in the menu to shut off the flicker reduction and as a result, the camera did not close the aperture down during live preview. You should have this option on your EPL5 as well. I don't on my OMD

I am praying for a firmware update, but I'm not a believer. But I might end up selling my Panasonic lenses (I only have those actually), because this behaviour is driving me nuts.

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photofan1986 said:

photofan1986 wrote:

Yep, that's really a shame!

And I must say that the live view behaviour when the aperture is stopped down looks awful. Coming from a dslr, I'm really considering going back to the good old design. This thing is really not fun to use. Look at this video showing the problem.

http://imageshack.us/photo/my-images/441/tsuapzafhdvymprfjloopj.mp4/

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