20mm f1.7 QUESTION

J

JerryB

Well-known member
I posed this question at Vimeo also, but thought I might get some more responses here.

After having a few days to actually play with the 20mm f1.7 and film "real" footage, I am having some issues with keeping focus.

I am shooting a documentary and have been previously using the stock lens and the occasional fast Canon primes in more controlled situations. I got he 20mm (40mm equivalent) because I needed something for low light that was wider than my 50mm (100mm equivalent). NOW THE QUESTION I POSE TO THE FORUM IS...

Does any one, with more experience using the 20mm f1.7 in particular, have an suggestion on how to keep better focus on a moving subject?

The auto focus is a bit too loud and slow for me to use all the time (which I kind of new from other posts already). Since this is obviously uncontrolled, an incredibly sharp focus is not always necessary, rather just capturing the moment the best I can (but I probably just want to have my cake and eat it too) What I have been doing as of recently is...

-Using manual focus to the best of my ability to capture focus while I move about the subject (which can be difficult given the electronic focus ring).

I realize that the more I shoot with the lens the better feel I will get for it, but I just wanted to know if anyone on the forum had any useful tips.

Thanks!
 
I’d say the first thing you need to do is make sure the firmware update for both the body and the lens is updated. Panasonic released firmware updates for some lenses in November so yours may not be up to date. It fixed some focusing issues.

Instead of using something like f/1.7, maybe you can try to use something like f/2.2 or f/2.5 although you may have to increase the ISO if their isn’t enough lighting. That way, the lens wont hunt as much trying to get stuff into focus.

As for the sound, if theirs other noises around you can hardly hear it but you can always try buying the external mic attachment. The mic will be further away from the motor noise than the built in mics.
 
As with above, if your subject is moving you really shouldn't be wide open. The autofocus shouldn't be audible with an external microphone, which you really need to have to do serious work.

This is why I don't use the Panny lenses at all; without a real focus ring with numbers on it there is pretty much no reliable way to pull focus. As you already said, you'll get a better feel for it the more you practice.
 
Camera Expert said:
I’d say the first thing you need to do is make sure the firmware update for both the body and the lens is updated. Panasonic released firmware updates for some lenses in November so yours may not be up to date. It fixed some focusing issues.
Click to expand...

Just an FYI, as far as I can tell the firmware update slows down the motor speed in order to quiet the motor. This has the positive effect of making focusing much quieter, but obviously the negative that if you are truly tracking a moving subject it's going to focus more slowly and may not be able to keep up.

-kap
 
An older firmware update did make it slightly slower but the one for November did make the auto focusing more accurate.

You have to update the older body firmware first (if it's not the September update) and then the lens firmware update.

http://www.dpreview.com/news/0911/09112501panasonicgf1lensesfirmware.asp
"Improved AF performance in movie recording"

http://panasonic.jp/support/global/cs/dsc/download/fts/index2.html

The latest update was on the lens when I shot these 2 videos and it was set to f/1.7.
http://www.dvxuser.com/V6/showthread.php?p=1855465#post1855465
 
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Does anyone know why this lens is unable to do the spot auto focus in the manual focus setting while filming like the stock lens can? I think if this were an option it would save me a lot of trouble for run and gun filming. This was probably the biggest disappointment over slow or loud auto focus. Does anyone know if this would be possible with a firmware update (although it seems doubtful to get it) or if there is a way to configure this?

Still a great lens even with it's few "video" faults.
 
D90GH1_eric said:
I don't think the stock lens can do this with GH1. Are you sure?
Click to expand...

While the camera is recording, it does if you keep the shutter release half-pressed. You can also click over to MF while you still have the shutter release half-pressed...but if you're not careful you can still mess it up. You also don't have use of the focus assist light while recording, which sucks.

The 20mm works exactly like the kit lens. Panny dropped the ball by not allowing AF-S when shooting video, IMHO. It would have been very useful for me....especially if they'd also have allowed the use of the assist light as well while recording.

But I'm a wedding videographer....probably not their target consumers of this camera. ;)
 
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