View Full Version : Zooming into Ground Glass on LEX
ozzymandius
01-15-2008, 05:51 PM
Did some recent tests with my new Letus Extreme and some Nikon prime lenses. I know you are supposed to zoom into the ground glass, just passed its edges, to fill the16x9 frame. However, I noticed that we could zoom to maximum, into a small section of the ground glass, without any apparent loss of resolution or visibility of the ground glass structure. The image on screen still looked beautiful. So rather than move the camera to get in closer to the subject, we just zoomed into the GG.
Question: is zooming all the way into the GG acceptable? Or will it lead to some kind of image defects? As mentioned, we did not notice any defects at all. Just wondering what other people's experiences are.
Kholi
01-15-2008, 05:56 PM
Been propgating this since I got my unit last year and I hope more people realize the advantages of being able to do this.
Things to keep in mind:
-GG Grain can become more apparent or "larger".
-Camera loses more light the further you zoom in.
-You're not changing your FOV, just cropping out of the image projected.
-HVX (Camera) handheld can suffer because the camera is at the end of it's lens. Thus making footage seem "shakier".
-You need to readjust your camera's focus as well. Although it may not SEEM that you've lost sharpness, you have. It might be a hair, but that hair is still good to have. AutoFocusing and writing down your findings will help in the future.
Keep in mind and keep testing and this new feature available to shooters will become invaluable. Mark my words. And Letus did it first.
ozzymandius
01-15-2008, 06:03 PM
Awesome! Thanks.
Good to know that we have another tool/technique at our disposal.
Kholi
01-15-2008, 06:05 PM
The scenario you described is just one of many situations that make it such a valuable tool. Imagine how much time you saved (seconds are DEAR when production is going) by zooming in?
Also, it's infinitely better than cropping the SAME shot in post, because you're only magnifying the ground glass before it hits compression, not noise or anything like that.
I have something else to demonstrate with this effect soon.
Kholi
01-15-2008, 06:09 PM
I only own the letus but was under the impression that this would work on any adapter with nice GG. Is that not the case?
I don't think it's the GG, but the distance from cam to ground glass that's the problem.
The flip units are moving the ground glass further away. That's also why the Brevis unit's achieving an edge-to-edge sharpness that wasn't seen before.
Pretty much has to do with your focal settings. That's my THEORY though. Not factual.
bwest
01-15-2008, 08:00 PM
-You need to readjust your camera's focus as well. Although it may not SEEM that you've lost sharpness, you have. It might be a hair, but that hair is still good to have.
Ahhhhhhhhh, Ive been incorrectly using this as a method of insuring fine focus, After I would then return the zoom to proper frame and hit record. Ahhhhhhhhh... now you tell me!
Kholi
01-15-2008, 08:03 PM
Ahhhhhhhhh, Ive been incorrectly using this as a method of insuring fine focus, I would back off the zoom to proper frame and hit record. Ahhhhhhhhh... now you tell me!
Nooooo don't do that. I can promise you if you look at the difference in sharpness when focusing that you're cheating yourself out of extra image clarity with the Letus EX.
Throughout the zoom the focus changes. You might not be able to see it on the LCD, but you can sure as heck tell when you're Component out on an LCD. There is a VERY small amount of sharpness loss when you zoom in, although it's so small you won't notice it unless you do the test with a huge screen component out.
Even a CRT + SD out shows the difference.
I implore that it's so tiny it doesn't matter for a shot where the zoom is moving during recording. If it's a shot where you zoom in to reframe, set your focus again.
bwest
01-15-2008, 08:30 PM
thanks Kholi