Slr 35 mm lenses verus mini 35 adapter at DVinfo.net

Brian Arwari · January 18th, 2005, 09:27 AM

Hi guys!
I'm sorry if I'm giong to ask a stupid question, but as you can see I'm new to the group.
I can't understand the difference between using a 35 mm SLR and the p +s 35 mm adapter. If I use a .5 coverter on the lens to eliminate the 7.2 magnification (like with the pappas system) effect would i still get a cine-like dept of field?
I read in some post that with the 35 slr lens you get a static ground-glass effect, whereas with the mini 35 the rotating glass would eliminate the glas grain.
I'm sure there must be many differences, otherwise poeple wouldn't spring 10k for the adapter.
Once again, sorry if the question is stupid and thanks for your clarifications.
Brian

Steev Dinkins · January 19th, 2005, 04:09 PM

The 7x magnification is the only reason you get a shallow depth of field since you are essentially now working with a telephoto lens. This is fine if you're okay with having to move many yards away from your subject and also having to have your subject far away from the background. This isn't practical in most situations. The goal is to be able to "easily" achieve the DOF you are wanting.

With small CCD cameras, your options are slim, complex, and/or expensive.

But the P+S, despite the money is the most genius invention I've seen in a long time.

For endless and painful research:

www.dvcreators.net/media/depthoffield.swf

www.mediachance.com/dvdlab/dof/index.htm

http://www.dvinfo.net/conf/forumdisp...?s=&forumid=70

Brian Arwari · January 21st, 2005, 05:11 AM

Steev, thanks a lot for the links!
I originally posted this question bevcause I was reading the Pappas article about rack-focus:
"and a few weeks later at another shoot we had an XL1 with a 15mm EOS lens and a special .42x wide angle lens converter. That made the XL1 EOS lens convert from a 108mm back to a 45mm (which is only 6mm away from the standard 16x)."
Reading this I was under the impression that If you used an adapter to convert a 15mm slr lens back to 45mm that you would get the exact same depth of field as if you were shooting with a 45mm slr.
If I undersood it correctly, the depth of field of video depends on the size of the ccd rather than on the actual focal lenth. The second link explained it very well.
Am I correct in thinking that if the xl2 had a 35mm ccd (like film), then we would automatically get the same depth of field as a flim camera?

Aaron Shaw · January 21st, 2005, 11:05 AM

Well it depends on the size of the imager and the focal length combined. Larger imagers take longer focal lengths to achieve the same field of view thus they have a greater DOF.

Steev Dinkins · January 21st, 2005, 03:26 PM

My understanding is yes, if the XL2 had a 35mm CCD you'd have the same depth of field as a 35mm film camera. Or course you'd need to do similar things to achieve shallow depth of field such as keeping the aperature open, and stopping down with filters if need be, etc. But it would be "possible".

Look at this monster here:

http://www.panavision.com/product_de...e=c0,c202,c203

It deploys a 35mm CCD. It also probably costs $200,000.

So that's why the mini35 and Pro35 are so revolutionary. $15,000 (mini35 and a DVX or XL2 cam) can get you film looks on Standard Def video.

However, I'm thinking moderators would say, the details of how to get a film look other than the P+S probably should be discussed elsewhere.

January 18th, 2005, 09:27 AM	#1
Brian Arwari New Boot Join Date: Oct 2004 Location: Rome, Italy Posts: 9	Slr 35 mm lenses verus mini 35 adapter Hi guys! I'm sorry if I'm giong to ask a stupid question, but as you can see I'm new to the group. I can't understand the difference between using a 35 mm SLR and the p +s 35 mm adapter. If I use a .5 coverter on the lens to eliminate the 7.2 magnification (like with the pappas system) effect would i still get a cine-like dept of field? I read in some post that with the 35 slr lens you get a static ground-glass effect, whereas with the mini 35 the rotating glass would eliminate the glas grain. I'm sure there must be many differences, otherwise poeple wouldn't spring 10k for the adapter. Once again, sorry if the question is stupid and thanks for your clarifications. Brian

January 21st, 2005, 05:11 AM	#3
Brian Arwari New Boot Join Date: Oct 2004 Location: Rome, Italy Posts: 9	CCD size Steev, thanks a lot for the links! I originally posted this question bevcause I was reading the Pappas article about rack-focus: "and a few weeks later at another shoot we had an XL1 with a 15mm EOS lens and a special .42x wide angle lens converter. That made the XL1 EOS lens convert from a 108mm back to a 45mm (which is only 6mm away from the standard 16x)." Reading this I was under the impression that If you used an adapter to convert a 15mm slr lens back to 45mm that you would get the exact same depth of field as if you were shooting with a 45mm slr. If I undersood it correctly, the depth of field of video depends on the size of the ccd rather than on the actual focal lenth. The second link explained it very well. Am I correct in thinking that if the xl2 had a 35mm ccd (like film), then we would automatically get the same depth of field as a flim camera?

January 19th, 2005, 04:09 PM	#2
Steev Dinkins Major Player Join Date: Nov 2004 Location: San Francisco, CA Posts: 613	The 7x magnification is the only reason you get a shallow depth of field since you are essentially now working with a telephoto lens. This is fine if you're okay with having to move many yards away from your subject and also having to have your subject far away from the background. This isn't practical in most situations. The goal is to be able to "easily" achieve the DOF you are wanting. With small CCD cameras, your options are slim, complex, and/or expensive. But the P+S, despite the money is the most genius invention I've seen in a long time. For endless and painful research: www.dvcreators.net/media/depthoffield.swf www.mediachance.com/dvdlab/dof/index.htm http://www.dvinfo.net/conf/forumdisp...?s=&forumid=70

January 21st, 2005, 11:05 AM	#4
Aaron Shaw Major Player Join Date: Jul 2004 Posts: 587	Well it depends on the size of the imager and the focal length combined. Larger imagers take longer focal lengths to achieve the same field of view thus they have a greater DOF.

January 21st, 2005, 03:26 PM	#5
Steev Dinkins Major Player Join Date: Nov 2004 Location: San Francisco, CA Posts: 613	My understanding is yes, if the XL2 had a 35mm CCD you'd have the same depth of field as a 35mm film camera. Or course you'd need to do similar things to achieve shallow depth of field such as keeping the aperature open, and stopping down with filters if need be, etc. But it would be "possible". Look at this monster here: http://www.panavision.com/product_de...e=c0,c202,c203 It deploys a 35mm CCD. It also probably costs $200,000. So that's why the mini35 and Pro35 are so revolutionary. $15,000 (mini35 and a DVX or XL2 cam) can get you film looks on Standard Def video. However, I'm thinking moderators would say, the details of how to get a film look other than the P+S probably should be discussed elsewhere.