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Using continous autofocus for the taking lens


AndreasK
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Hello,

 

I'm new to this forum and also to anamorphic shooting, though I worked as steadicam operator on projects with rented hawk lenses before. I downloaded the anamorphic shooters guide, read the forum and watched videos so far.

 

Recently I purchased my first anamophic lenses on ebay: http://www.ebay.com/itm/290889768316 a set of Rathenower Rectimascopes 48/2x which I might get soon. Videos on youtube confinced me about how sharp they are. One mount option is exactly like Edwin Lee and tferradans did with their Hypergonars:

 

http://www.eoshd.com/comments/gallery/album/29-hypergonar-hi-fi-2/

http://www.flickr.com/photos/edwinylee/sets/72157625790618742/

 

However, the Rectimascopes are dual focus and I'll soon have the ability to test how this handles in real shooting. But after reading what JohnBarlow did with his Moeller rig and the option to use autofocus lenses with single AF by half pressing the camera shutter http://www.eoshd.com/comments/topic/2398-my-compact-moeller-322x-rig-scope-on-a-rope  I wonder if it is not possible to use a camera with continous autofocus for the rear lens at all. This way one would only have to focus the anamorphic lens and the rear is adjusted by the camera with contrast autofocus. No reason to fear the autofocus might adjust to the backround in this setup, though.

 

I have a Canon 60D and no autofocus lens at the moment since I use my old Contax/Yashica lenses for video and also photos but what I've read in the manual their autofocus won't allow for continous and fluent focus revision. But a Panasonic GH series camera might do the trick and that would be a good reason to buy one. Eventually there is somebody who already tested this approach with dual focus lenses?

 

Thanks,

Andreas

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With a dual focus setup you can't use continuous autofocus. The autofocus lens will adjust the focus, but you'll have to adjust the anamorphic as well if the distance to the subject changes.

 

Thanks, that's exactly what I mean... it would be alright if I only need to adjust the anamorphic lens for distance changes. I can do that either myself in ENG style or a assistant can adjust focus with a FF according to marks. That would allow for a normal feature shooting style.

 

So you think the autofocus lens will adjust correctly? Would be great if somebody with a GH series camera could give it a try :).

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Thanks, but do you think it will be smooth enough during a shot? In my 60D manual it seems that the autofocus would "search" too much and that it's necessary to press the shutter half way... what I read in the GH1 manual sounds much better. I'm hoping for an continous adjustment not even noticeable.

 

I'm planning to glue a standard filter size step ring to the front for diopters like Edwin Lee did:

http://www.flickr.com/photos/edwinylee/5392635963/in/set-72157625790618742

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Hi Andreas
 
You should know that the units you purchased are much bigger than my Moeller
 
1) They are large and weigh 1100g each
2) The closest focus is 6m, so you must use diopters, but they are very sharp.
 
Having said that, the answer to your question regarding autofocus is as follows.
 
On the Nex (including FS100, FS700) you can focus the scope and the NEX will track the focus automatically, so follow focus of a subject in motion is possible. Alternatively you can use the touch screen to select focus after focussing the scope which is useful for pull focus.
 
On the Canons, Nikons you can half press the shutter as I mentioned in the other thread.
 
Basically it reduces the task to a single focus which is done on the scope.
 
I aim to put up a video in a few weeks to show this procedure.
 
 
edit, for follow focus you must use a lens designed for autofocus video, not an older AF lens
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Thanks @andy, could you tell me with witch cameras you tried it?

 

@John, do you need to press half shutter with your NEX 5N for AF during video recording or does it do the autofocus anyway? I read a few tests that it's got one of the the fastest autofocus systems. A NEX might be even nicer than a Lumix because of the larger sensor...

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On the NEX in video mode you have half press shutter button AF or touch panel focus AF and continuous object tracking AF.

 

The key is the lens used. With your scopes the E1.8/50mm would be a good match, give great bokeh and you could definitely get a great 2.35:1 crop.

 

Basically just focus the scope and let the NEX find focus, which it does without hunting in good light.

 

 

@John, do you need to press half shutter with your NEX 5N for AF during video recording or does it do the autofocus anyway? I read a few tests that it's got one of the the fastest autofocus systems. A NEX might be even nicer than a Lumix because of the larger sensor...

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