Technical questions before i buy.

[Nils Hoover]

For the most part i understand how these 35mm adapters work. I have searched the forums and read much of many of the posts, but still its hard to sort through, so i still have some questions, which are actually quite large ones.

1. Once you have one of these adapters do you set the focus and the aperture on your camera to some thing set and then manually change it with the lens? or do you then have to focus and change the aperture with both the camera lens and the SLR lens?

2. Looking on the websites its hard to tell which lens mounts they support. I see the M2 supports The EOS mount (which i would like to use because i have a cannon EOS still camera) But it isnt obvious which other adapters have that mount available.

3. Is the "follow focus" or what ever on the M2 just a nob on the side so you don't have to reach around to focus?

4. This one is pretty obvious, but all the lenses need to be completely manual right? otherwise the aperture would just be stuck.

Any way, sorry if all this information is all easily available, but it wasn't obvious to me on most of the posts i have read.

[Carl Jakobsson]

I'm not an expert but....

1) All focusing is done with the SLR-lens. The only focusing and zooming you have to do with the cam is on the groundglass of the adapter. This is done once when installing the adapter. When the focus is set on the ground glass you'd stick with that settings and do all focusing/zooming with the SLR.

4) Manual aperture is a plus. My Canon F1.4 SLR was very cheap because the aperture is stuck at 1.4 (fully open). I solve this by adjusting the aperture on the cam instead. The drawback is of course that you miss the SLR:s characteristics at different apertures. This solution works for me however.

[Nils Hoover]

thanks carl, and for the rest of the questions i looked around and figured them out for the most part. I still have some questions though.

I have a Panisonic DVC30 which is like a not as good version of the DVX100. The lens on the dvc30 is a 43mm. For the M2 and the brevis that means i will need to get a step up ring to 58mm correct? for the sgpro i would need a bunch of rings and would be kind of silly because that is 72mm right?

Also i have read from posts from another users that has the DVC30 that an achromat is not needed, atleast he took his out of his letus35 because it wasn't needed. does any one know if this is true for this particular camera, or does it just depend on which adapter?

I am still not even entirely sure what an achromat does. Is it basicaly just a macro lens that allows you to focus on the focusing screen?

[Ben Winter]

Originally Posted by Nils Hoover

thanks carl, and for the rest of the questions i looked around and figured them out for the most part. I still have some questions though.

I have a Panisonic DVC30 which is like a not as good version of the DVX100. The lens on the dvc30 is a 43mm. For the M2 and the brevis that means i will need to get a step up ring to 58mm correct? for the sgpro i would need a bunch of rings and would be kind of silly because that is 72mm right?

Also i have read from posts from another users that has the DVC30 that an achromat is not needed, atleast he took his out of his letus35 because it wasn't needed. does any one know if this is true for this particular camera, or does it just depend on which adapter?

I am still not even entirely sure what an achromat does. Is it basicaly just a macro lens that allows you to focus on the focusing screen?

As far as I know, the M2 and Brevis are 72mm, not 58mm.

A macro is an optical filter, typically double convex that allows cameras to focus on very close-up objects. This is where "macro photography" comes from. If you ever see really close-up pictures of a bee on a flower, for instance, chances are the photographer is using a macro. Now, the word "achromat" comes from a type of macro, called an "achromatic doublet" which means the macro consists of two pieces of glass optically glued together, a double convex and a plano-concave which results in a plano-convex lens. This helps reduce the chromatic aberration (typically seen as a blueish smear at the edge of a bright contrasty line) towards the edges of the image. An achromat typically has a better image than just a regular macro. Both the M2 and Brevis companies offer achromatic doublets as macros for thier imaging devices, but they're much, much more expensive.

Here is a diagram of a regular macro compared to an achromatic doublet:
http://www.optics.arizona.edu/Nofzig...tures/3_33.jpg

See how the lines all meet at the same point with the doublet? That means no color separation (which is what chromatic aberration is: http://www.dpreview.com/reviews/Adob...CA_01_ORIG.jpg).

Yes, the need for a macro pretty much depends on the adapter and camera used.

[Nils Hoover]

alright that is very helpful for understanding an achromat.

If all 3 of the m2, sgpro and the brevis are 72mm does that mean that really the only one i should consider is the letus35 (those are the main ones that i see people have). or would it still be realistic to be looking at the other ones, and if so how would i deal with the large gap (42mm-72)?

[Sam Jankis]

Sweet Brevis/DVC30 setup:
http://www.247pictures.de/TheMachine...y-komplett.jpg
http://www.247pictures.de/TheMachine...-komplett2.jpg

[Nils Hoover]

damn that is sweet