"Farris35" Pre-beta adapter - troubles

[MiniMan]

Hello fellow dvxusers once again!

I've finally started my very first 35mm adapter, and I'm now ready to really enter this 35mm world!:Drogar-BigGrin(DBG) It's all going to be made inside a Farris bottle, similar to the Pepsi35, or more like a Pepsi35-wannabe.

But the thing is, I have a DVX100E (less macro focusing), and yet no 10+ macro. I have decided to build a macro-less adapter, and then get a macro of ebay if it works fine. It seems to work out nice, I have two EF zoom-lenses, 28-80mm and 80-300mm (or something like that, too much tele anyway). The GG I use is a DVD-case, seems to work great for its purpose.

Now I havent bothered to adjust the proper distance between the lens and GG yet, so the whole picture is literally out of focus all the time. BUT, there is a problem: I have this light spot in the middle of the frame all the time. I haven't seen anyone else mention this on any of their adapters yet.

Posting this footage is [B]really[B] embarrasing, simply because is sucks so much, because of the improper distances and lack of macro. But I don't think that this light spot has anything to do with that?

http://tore.thedigitalline.com/F35_web1.jpg

http://tore.thedigitalline.com/F35_web2.jpg

[MiniMan]

Anyone? Yeah, I know, it's a really dumb question...

[marlenedegrood]

What type of focus screen are you using? It looks like one with a center circle in it.

[MiniMan]

I'm using a frosted DVD-cover as a focus screen, and it doesn't have a circle on it. The circle always follows the projected image from the lens. :( Should I try with a different focus screen or what?

[marlenedegrood]

Sorry......just reread your post and see where you said DVD Case screen. Is your 35mm lens wide open?

[MiniMan]

I'm not sure. There doesn't seem to be an aperture ring on the EF-lenses? Cannot find one at least, and it's a zoom lens too. Sounds bad?

Any advice on how to control aperture?

[Dennis Wood]

Mini, here's a few tips.

The Canon EF lens aperture is electronically controlled by the camera. This means that off the camera, it will stay wide open, and therefore you cannot stop it down. You'll have to use ND filters to bring light levels down.

You're probably seeing hotspotting. If you search "hot spots" or "condensor" here and over at dvinfo.net, you'll find that you likely need a condensor lens in front of your GG.

[MiniMan]

But, if I get, say a canon 50mm
http://cgi.ebay.com/Canon-FD-50mm-f1-4-Lens-F-1-A-1-AE-1-MF-F1-NR_W0QQitemZ7603089775QQcategoryZ48552QQrdZ1QQcmdZ ViewItem
With an FD mount, of course, which is below F 2.0, would I get rid of the hot spotting then?


If you have different cameras, pick the fastest lens. It's the f numbers printed on the front ring of the lens. F 1.7 is regular, but F 1.4 is faster and gives a bright image. Higher than F 2.0 can give problems with hot spots and light loss.

Oh BTW, I think that the F-stop on the lens I'm using now is really low. I can light a wall with a 300W fluorescent, and still have to use +12db grain to get it properly exposed...

[marlenedegrood]

I would think, that altough off the camera the lens is wide open, when it's connected to the mount it is stopped down and that's what could be causing the hot spot. If you look at the pictures posted, it seems like what you are seeing is a hot spot created by the lens.

Look at the front of the lens when mounted and see if the aperture is wide open or stopped down.

[MiniMan]

Now I think I'm just plain stupid. I can't see whether the aperture is changing or not when it's mounted on the EOS300 either, when changing the aperture from F3.5 to F32.

And also, the "hot spot" in the image seems to focus differently than the rest of the image too.