An experiment for those wanting a longer lens

Re: An experiment for those wanting a longer lens

Just in case some of you reading this thread are thinking about using one of these close up diopters as a means of magnifying the image so your lens appears to be more telephoto...It wont work. Well not completely. You loose the ablility to focus at infinity with close up diopters. On the other hand you will be able to focus closer. Just wanted to clear that up so no one wastes their money.

-Brett Erskine
 
Re: An experiment for those wanting a longer lens

[quote author=Brett Erskine link=board=Links;num=1089144877;start=15#20 date=07/09/04 at 18:26:32]J appears to be more telephoto...

-Brett Erskine[/quote]

what do you mean by that?

no, really* i * was looking for magnification.
 
Re: An experiment for those wanting a longer lens

Diopters may increase the magnification like a telephoto lens BUT they also loose their ability to focus at or near infinity so they are only a partial solution to increasing the telephoto ability of your lens. I only mention it because while most people know the difference some people might be thinking that diopters will do the same as a teleconverter. These things can be pricey and you want to make sure you are getting the right optics for your application.

Diopters for close up work - Teleconverters for telephoto work.

On a side note XL1 users can fit 35mm film lens to their camera to effectively increase focal length any given canon film lens by a factor about 7X. This is possible by a special Canon made adapter. Unfortunately since we can't remove our DVX100 lens we wouldnt be able to do the same thing. However I remember seeing some adapters out there that let you hook up your video camera to anything from binoculars to telescopes. And even another idea is to use long focal length film lenses with a (homemade) Mini35.

I'd love to hear more from people because it would be nice to increase the focal length of the DVX100. Wild life and surfing videography are two applications.

Brett Erskine
www.CinematographerReels.com
 
Re: An experiment for those wanting a longer lens

Okay I received the Century Optics 1.6x teleconverter today and what a hunk it is. It's huge and heavy...so much for fitting on my matte box... :(

Anyway, I tried both my 58mm 2x and the 1.6x in combination and it works really well, giving me an effective focal length of 144mm. As mentioned before there are extreme limitations in the zoom range, namely 99-100 :)
 
Re: An experiment for those wanting a longer lens

what does that do to your DOF?

thats a lot of glass. what mattebox do you have?
 
Re: An experiment for those wanting a longer lens

There is a very narrow depth of field when fully zoomed in with this config. I'll have to play with it and post some stills.

I have a cavision 4x4 bellows mattebox....
 
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