Simple question, complicated answer.

TMY

TMY

Well-known member
I've been searching/looking into 35mm adapters and I have been wondering, why couldn't you just get almost a stopdown ring and attach the lens to it. I believe the theory for most 35mm adapters is to get a more "film" look, dof, and film grain, but what is stopping me from, basically, gaffing a 35mm lens to the front of my dvx? (I'm oversimplifying here, I would never even consider gaffing one lens to another) Are there focal issues that necessitates the need for the ground glass or something even more complicated?

Thanks for the help.
 
Matty_g said:
nothing is stopping you from doing that but you will not have 35mm dof or fov.
Click to expand...

Technically, this is not quite correct. You'll get the same DOF as the lens you put on, but not the same FOV. It's not the lens, it's the sensor. The small sensor of the camera will not "see" the full FOV of the lens, even though the DOF will be the same for that given focal length. Even if you can graft a 35mm lens on to the camera, you'll end up with an extreme telephoto lens that's completely useless for most applications. The Canon EF to XL mount adapter does exactly this; and the magnification factor is something like 7.8.

The purpose of a 35mm adapter is to provide a ground glass area that's as large or in many cases larger than the 35mm cinema sensor. This is what's going to give you that 35mm FOV and by extension the DOF associated with those lenses. It has little to do with film look or film grain. Most 35mm adapter manufacturers work very hard to make sure that no grain shows up in the footage, and whatever filmlook is associated more with the lens you used and your cinematography skill.
 
Putting lenses on top of other lenses is also a recipe for really ugly chromatic abberations and distortion. Your camera's stock lens isn't designed to look through another lens. Nor is a 35mm lens designed to project an image onto another lens. When you try doing that oddities will occur. And said oddities will most likely be different with every lens you screw on which will make editing your footage together with a cohesive look much harder.
 
I see where you're coming from, Dan and I should have made myself more clear so as not to scare people away from using lens converters (which I do). But I stand by the statement that anytime you put a lens in front of another lens you risk chromatic abberation. And the DVX isn't designed to look through other lenses. Those lenses are designed, after the fact, to work with the DVX.

Whenever someone reviews a wide angle adapter or telephoto converter what is one of the first things they talk about? How much Chromatic Abberation it introduces. It's because CA is a fact of life when you put glass on glass. Good adapters are simply designed to minimize CA. An SLR lens isn't designed with the DVX100's stock lens in mind or the stock lens of any camcorder. So you're chances of getting CA with it are much higher when it's attatched to a stock lens. But the risk of CA comes anytime you put a lens in front of the stock lens.

davide
 
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We've demonstrated that at least one camera's CA can actually be reduced by an adapter, and it's something widely reported by our XH-A1 users. Predicting what happens when you put an adapter out front can be a tricky business as there are many factors to consider. We continue to be surprised as we explore adapter performance using the rear illuminated DSC labs OSGs. Check the clip on XH-A1 chromatic aberration testing: Its the second last on that page. The Canon cameras demonstrate nearly flawless edge to edge sharpness with the MP.1 flip making it a strong recommendation for use with our system. This behaviour is as counter-intuitive as is the clip on Brevis light loss, but it demonstrates the need for objective and careful testing...something we do a lot of these days.
 
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