What is it about the EX1 that causes problems with 35mm adapters?

T

Texanite

Well-known member
It seems like people are always talking about needing a fix for their EX1, with new achromats or whatever being produced just for that purpose. What is it specifically about the EX1 that causes problems with the existing adapters?

Is it the lens on the EX1? Too big? Too small? Too thick? Too thin? And what is the problem, exactly? CA? edge to edge focus? Something else?
 
So it's the fact that the EX1's lens is designed to work with 1/2" sensors that causes the issue?

Is the problem that you can't get close focus using the previously existing 35mmadapter achromats, or can you get focus but there's something else screwy?
 
I wouldn't say its neccessarily because it is a 1/2" chip, though perhaps that's all it is. What I hear from manufacturers is that it is just optically weird and hard to work with for them. Look at all the problems people have had designing a wide angle adapter. Its an odd beast. I don't know anything about optics though so can't say more.

Lenny Levy
 
How does the LEX fair without the new achromat? I havn't upgraded mine, mainly because it was one of the first ones made and would have to be sent in for the update. On the HVX its really not a huge issue although I'm sure it would benefit from some edge sharpness. It sounds like the EX1 is a different beast entirely.
 
Completely different Beast - as with the Brevis, corner to corner sharpness won't clear up till you are at f8 on the Ex-1 - Just about when you begin to lose sharpness from the Ex-1 lens as well. So you can shoot outside if you are careful.

The new Letus achromat cleared that up. Supposedly the same on the SGPro . Brevis is going about a different type of solution altogether with a new diffusion screen. If they succeed it will probably be another case where people will go crazy here and shout "voodoo."


BTW both the SGPro and Letus EX-1 fixes cannot achieve full SLR image size- pretty much about Academy even with SLR lenses.

Lenny Levy
 
Last edited:
What do you mean by "full SLR image size - pretty much about Academy even with SLR lenses"?

I'm looking into purchasing an EX1 and a Letus, so I'm curious to what to look out for.

Mike
 
Cine 35mm (academy) is a smaller frame size than SLR 35mm since the film is moving sidewise in an SLR and vertically in a movie camera.

On an HVX with say a Letus or especially a Brevis you can generally get a good usuable image that shows the full field of view that the 35mm SLR lens is designed to project on an SLR. On the Ex-1 with a Letus or an SGPro there is vignetting on the sides that forces you to zoom in on the video camera to more of the center of the image. Probably to something closer to academy aperture on a Cine camera. This is apparently due to the optics of the EX-1 lens. Whetehr that is speciufically a function of the 1/2" sensor I don't know.

Lenny Levy
 
Full slr / academy refers to field of view. If an adapter offers fullframe slr field of view then when you put a 35mm lens on it you get the same image as you would if you were to put that lens on a 35mm film SLR. Academy ratio refers to the field of view of motion picture cameras. 35mm motion picture film is smaller than 35mm still film, so the field of view is more narrow.

This becomes an issue for some with wide angle lenses. Since full frame gives you just that, the full frame, it allows you to get wider angle shots with your lenses than if you were shooting academy ratio. To get the same field of view as a 24mm lens shot at full frame you would need something like an 18mm lens at academy.

Here's a link to a post that gives some more information on the relative sizes of the different formats: http://www.reduser.net/forum/showthread.php?t=2732

davide
 
I has nothing to do with the fact that it uses 1/2" chips. The problem is that the camera does not focus close enough even while using the macro setting on the lens. When you finally focus on the groundglass you cannot fill the frame. I think the closest focusing distance is 8 inches.
 
Winston Vargas said:
I has nothing to do with the fact that it uses 1/2" chips. The problem is that the camera does not focus close enough even while using the macro setting on the lens. When you finally focus on the groundglass you cannot fill the frame. I think the closest focusing distance is 8 inches.
Click to expand...

Now there's a clearcut answer. Thanks Winston.
 
I have no problem focusing on the ground glass with my Ex-1. I don't understand what you mean about not being be able to fill the frame. MNaybe that is the issue but i don't get it from what you're saying.

The manufacturers I've talked to have alluded to optical issues with the design of the EX-1 lens itself, but I didn't understand their complaints.

Lenny Levy
 
If you can cover the full image maybe you can tell us which achromat you're using. I have a person in England that had the same problem that I have been reading about with the adapter and this particular camera. He told me that he was not able to fill the frame even while using the macro mode , and he trying to frame a 6x4.5cm groundglass which is more than twice the size of 35mm. If you've had sucess doing it, please share it with us. I even shipped him a spacer to see if that would help.

According to him it failed, so perhaps he's doing something wrong.
 
I still don't understand what you mean about covering the full image. Why would anyone expect to cover a 6x4.5cm groundglass which is more than twice the size of 35mm. The 35mm lens isn't designed for that anyway.

. With a Letus Extreme and the right achromat, you can fill the screen with a good looking in focus image - no vignetting . Using Nikon lenses it does not cover the same field of view as a Nikon SLR lens, It will vignette if you try to do that, but if you zoom in past that it can producer lovely sharp flat images at something closer to academy aperture.

_ Lenny
 
It is now 100% possible to use full SLR format (in this case wider, at 38mm wide frames) with the EX1 and our MP.1 flip. This clip was made using Zeiss 28, 35, 50, 85 and 100mm ZF mount (Nikon) lenses.

Lenny is correct in that the issue you're referring to indeed one with with the EX1 lens itself.
 
My guess with the EX-1 lens ( only a guess) is that it is using the same physical size lens as a typical 1/3" chip camera but somehow managing to get it to cover a larger area - the 1/2" chip. This probably requires optical compromises and some "trickery". It is I believe a CAC lens, which means that computer optimisation on the camera is compensating for aberrations in the lens itself. This may also explain the Ex-1's problems with vignetting and back focus.

lenny
 
You must log in or register to reply here.
Back
Top