Looking at the Letus Extreme

Todd Giglio · October 27th, 2007, 08:32 AM

Quote:

Originally Posted by Roger Lee

Did someone answer Mickey's question?

I'm curious about this as well.

Thanks

Rog Lee

I'm pretty sure you can zoom into any size of the GG, but keep in mind that this will also increase the size of any grain that can be seen from the diffuser. I would try to keep the potential grain size down IMHO.

Steven Dempsey · October 27th, 2007, 08:34 AM

No, the camera is zooming in and focusing on the picture that is projected on the ground glass. The field of view of that picture is 200mm.

Look at it like the ground glass is a tiny little movie screen with a movie being projected on it. You are just capturing that little movie with your camera.

If you were to zoom in completely, all you are doing is blowing up pixels, similar to how a digital zoom works rather than an optical one.

Does that make sense?

Check out the basic theory of adapters here: http://www.mediachance.com/dvdlab/dof/index.htm

Shiv Kumar · October 27th, 2007, 03:37 PM

Micky, Roger,

Typically, you wouldn't use the zoom on the camera when you're using the Letus (or any 35mm adapter). Essentially, you zoom in onto the ground galss of the Letus such that you don't see the edges of the ground glass or Letus body etc. Once you're get that setting, you don't touch the zoom on the camera. You can zoom in if you want and you do get the effect of zooming in or more telephoto but (don't remember why now) you don't want to do that for "quality" reasons.

So essentially, you'd use an SLR lens with the focal lenth you want. You can use a zoom lens instead of a prime. I've not tried this myself, and nor have I seen good footage of this in use. I do plan on using a zoom lens (70-200mm f/2.8L) when I get my Letus Extreme with the Canon EF mount.

I hope that helps?

Shiv.

Todd Giglio · October 27th, 2007, 09:58 PM

Quote:

Originally Posted by Steven Dempsey

No, the camera is zooming in and focusing on the picture that is projected on the ground glass. The field of view of that picture is 200mm.

Look at it like the ground glass is a tiny little movie screen with a movie being projected on it. You are just capturing that little movie with your camera.

If you were to zoom in completely, all you are doing is blowing up pixels, similar to how a digital zoom works rather than an optical one.

Does that make sense?

Check out the basic theory of adapters here: http://www.mediachance.com/dvdlab/dof/index.htm

Steven (if you were responding to me), when I said that you could zoom in (and blow up) any size of the GG, I meant exactly what you said "zoom with the camera". I do know the basic principals of these adapters (I have the M2, Brevis and Letus Extreme) and my main point was what you also mentioned (that you'd only be blowing up the grain size from the adapter; you really wouldn't be blowing up the pixels unless you really were using a digital zoom since the camera lens is actually doing the zooming). I hope that makes sense too (I hate for anyone to get confused over this discussion).

Todd

Roger Lee · October 28th, 2007, 09:55 AM

Thanks all for the info.

If I understand correctly, with the Letus extreme, if you are using a 200 mm lens, that's what you get is a 200mm field of view...the same field of view you would get if you attached the 200mm to a DSLR.

Tx

Rog Lee

Mickey Mackwan · October 28th, 2007, 02:28 PM

thanks steven and shiv for the knowledge

Phil Bloom · October 28th, 2007, 03:14 PM

Quote:

Originally Posted by Roger Lee

Thanks all for the info.

If I understand correctly, with the Letus extreme, if you are using a 200 mm lens, that's what you get is a 200mm field of view...the same field of view you would get if you attached the 200mm to a DSLR.

Tx

Rog Lee

More or less. There are variables. For example the Letus Extreme and Brevis have a frame size larger than 35mm film SLR, and definitely larger than a DSLR. Which would mean if you use that frame fully it's wider than 200mm, but if you zoom it a tad you will match it.

Shiv Kumar · October 29th, 2007, 03:59 AM

Roger,

Also note that most DSLR are croped frame. That is on the Canon side the 5D and 1D family are the only full frame DSLRs.

So if you've got any other DSLR and you've attached a lens with a 200mm focal length you're really seeing a narrower field of view. This factor it typically 1.6 meaning that with a 200mm lens you're really seeing the field of view of 200 x 1.6 = 320mm

Now in the Letus you'll get (if you zoom in just a bit as Steven explained earlier) a 200mm field of view and not 320mm.

I mention this just in case you're not familiar with this since you mentioned DSLR and not "full frame DSLR. So just keep that in mind.

Shiv.

October 27th, 2007, 08:34 AM	#17
Steven Dempsey Disjecta Join Date: Apr 2004 Location: Seattle, Washington Posts: 937	No, the camera is zooming in and focusing on the picture that is projected on the ground glass. The field of view of that picture is 200mm. Look at it like the ground glass is a tiny little movie screen with a movie being projected on it. You are just capturing that little movie with your camera. If you were to zoom in completely, all you are doing is blowing up pixels, similar to how a digital zoom works rather than an optical one. Does that make sense? Check out the basic theory of adapters here: http://www.mediachance.com/dvdlab/dof/index.htm __________________ Try my Digital Therapy: http://www.pinelakefilms.com/digital_therapy.html Films on ExposureRoom: http://exposureroom.com/members/disjecta.aspx/videos/

October 27th, 2007, 03:37 PM	#18
Shiv Kumar Major Player Join Date: Jul 2007 Location: Gainesville, VA, USA Posts: 327	Micky, Roger, Typically, you wouldn't use the zoom on the camera when you're using the Letus (or any 35mm adapter). Essentially, you zoom in onto the ground galss of the Letus such that you don't see the edges of the ground glass or Letus body etc. Once you're get that setting, you don't touch the zoom on the camera. You can zoom in if you want and you do get the effect of zooming in or more telephoto but (don't remember why now) you don't want to do that for "quality" reasons. So essentially, you'd use an SLR lens with the focal lenth you want. You can use a zoom lens instead of a prime. I've not tried this myself, and nor have I seen good footage of this in use. I do plan on using a zoom lens (70-200mm f/2.8L) when I get my Letus Extreme with the Canon EF mount. I hope that helps? Shiv.

October 28th, 2007, 09:55 AM	#20
Roger Lee Major Player Join Date: Sep 2007 Location: Western Minnesota Posts: 227	Thanks all for the info. If I understand correctly, with the Letus extreme, if you are using a 200 mm lens, that's what you get is a 200mm field of view...the same field of view you would get if you attached the 200mm to a DSLR. Tx Rog Lee

October 28th, 2007, 02:28 PM	#21
Mickey Mackwan Regular Crew Join Date: Jun 2007 Location: sydney Australia Posts: 60	thanks steven and shiv for the knowledge

October 29th, 2007, 03:59 AM	#23
Shiv Kumar Major Player Join Date: Jul 2007 Location: Gainesville, VA, USA Posts: 327	Roger, Also note that most DSLR are croped frame. That is on the Canon side the 5D and 1D family are the only full frame DSLRs. So if you've got any other DSLR and you've attached a lens with a 200mm focal length you're really seeing a narrower field of view. This factor it typically 1.6 meaning that with a 200mm lens you're really seeing the field of view of 200 x 1.6 = 320mm Now in the Letus you'll get (if you zoom in just a bit as Steven explained earlier) a 200mm field of view and not 320mm. I mention this just in case you're not familiar with this since you mentioned DSLR and not "full frame DSLR. So just keep that in mind. Shiv.