Glass Glass Glass...

[Bonedog]

Ok, I've had my DVX for quite some time now, and am beginning to look at different upgrade options. However, I've recently gotten into the market for a DSLR for still photography. Being a frugal minded type of guy, my first question was "Can I rig my DVX with DSLR lenses?" It seems that I should be able to.. but there also seem to be all sorts of intricacies in optics that I'm not quite sure. But regardless, I'd like to get a better understanding of what it takes to use different glass on the DVX.

I've seen plenty of rigs using the Letus 35mm adaptor- what does that do that a 72mm-Xmm step down ring wouldn't (It obviously does something)? Why are 35mm lenses such a big deal in the first place, when Canon and Nikon both have a variety of different sized lenses with very long focal lengths? Or am confusing filter threads with some sort of interchangeable lens interface. If you want to use any non stock lens, do you have to have rails period, or are their smaller lenses out their that can go with out them. As you can see I have all sorts of bits and pieces.. but not a very clear understanding. Wondering if some of you fellows could set me straight

Thanks,
~Bonedog

 

[Alex H.]

35mm lenses literally project the incoming image onto a plane, be it an image sensor or a strip of film or a focusing screen. They will not pass the image on properly straight to your DVX's lens. What the 35mm adapter does is to provide a focusing screen on which the image from the lens is projected. A 72mm diopter lens between the DVX and the focusing screen allows the DVX to macro focus onto the screen, recording the image from the 35mm lens (35mm, in this case, used as a blanket term to refer to lenses used in 35mm photography).

Rails are necessary to support the front-heavy weight of the adapter rig, and possibly the lens in extreme cases.

As for the why: folks figured out that using these 35mm adapters allowed for the use of a wide selection of lenses, mostly primes, for a much more cinematic image acquisition. Don't be mislead: lots of people started calling them "DOF adapters" since they could now get much shallower depth of field with these new lenses; however, shallow focus is a tool to be used intentionally and sparingly. What you really get is a little bit of perceived "grain" from the focusing screen (emulating film stock) and true lens selection.

There are several adapters out there, both manufactured and DIY. One thing to consider is that the lens actually passes the image backwards and upside down, and so what the camera records is as such. It has to be flipped at some point. It's hard to shoot with a skewed image, and two of the in-production solutions are external LCD monitors or flip units for the adapters. The former requires use of an external LCD monitor (Marshall, Lilliput, Delvcam, Varizoom, Ikan, etc.) that has a "flip feature. This feature corrects the image in the monitor, but it's still recorded the wrong way and must be flipped in editing. The latter, flip units, offer optical correction of the image before the camera records it.

There's an entire forum here at DVXUser dedicated to 35mm adapters. Plenty of good info on which one and why. And since lots of folks are moving to DSLRs and other cameras like the AF100, there are deals to be found on used 35mm adapter rigs (check the DVXUser Marketplace) as people no longer need them.

Of course, if you're going to get a DSLR, you could start shooting on that and forgo the trouble of a 35mm adapter.

 

[Bonedog]

That makes sense, but I guess I'm still not clear on what 35mm describes about the lens, and why its used so exclusively. I mean, why not use a 58mm lens with a 58mm adapter. Is 35mm just considered industry standard?

 

[Alex H.]

That makes sense, but I guess I'm still not clear on what 35mm describes about the lens, and why its used so exclusively. I mean, why not use a 58mm lens with a 58mm adapter. Is 35mm just considered industry standard?

We're talking about two different terms here.

35mm adapter refers to use of lenses traditionally used in 35mm photography... 35mm being the size of film stock used. This has nothing to do with the lens.

The other term has to do with the focal length of the lens: 24mm, 35mm, 50mm, 85mm, 105mm, etc. The lower the number, the wider the angle (or, the wider the field of view). And zoom lenses will be labeled with the two ends of their focal range, such as 18mm-55mm or 80mm-200mm.

So, you can have a 35mm film lens that has a focal length of 50mm, or a focal length of 35mm, or 20mm, or...

 

[Bonedog]

We're talking about two different terms here.

35mm adapter refers to use of lenses traditionally used in 35mm photography... 35mm being the size of film stock used. This has nothing to do with the lens.

The other term has to do with the focal length of the lens: 24mm, 35mm, 50mm, 85mm, 105mm, etc. The lower the number, the wider the angel (or, the wider the field of view). And zoom lenses will be labeled with the two end of their focal range, such as 18mm-55mm or 80mm-200mm.

So, you can have a 35mm film lens that has a focal length of 50mm, or a focal length of 35mm, or 20mm, or...

Gotcha. I appreciate it.