Smaller DOF at DVinfo.net

Dario Corno · October 25th, 2004, 04:40 AM

Hi averyone, first of all I want to apologize for my terrible english...then, on to the question.

I have an XL1s camera, and I've fallen in love with it, I'm doing reflex photography since some years now, and whould love to achieve the same SMALL DOF I can get with my reflex camera on the Xl1s.
I've tried the best setup with the XL1s in a very sunny day, but can't get that well "blurry" background I can get with the reflex lenses.
Now I was thinking about an EF adater, will the f-stop of the EF lens be affected by the adapter (or camera ccd) ?
if I buy a very light lens, with an high f-stop will it work on the XL1s the same as on the reflex camera ??

Thanks, and sorry for my english and my (maybe dumb) question. :D

Rob Lohman · October 25th, 2004, 04:58 AM

That will not work due to the magnification factor (7.2x). Sorry.

You can get a bit smaller DoF by doing the following with the
default lens on the XL1S. Open the iris as much as possible
(f2.8 for example, which might mean you need to add ND filters
[either onboard and/or external)

Other than that you will need to get a true 35mm adapter to
use true 35mm lenses. Basically their are two options. Buy or
rent the P+S Technik mini35 (costs $10.000 to buy excluding
lenses) or build your own (see our Alternative Imaging forum)

Andre De Clercq · October 25th, 2004, 06:21 AM

Rob, sorry but it has been repeated over and over again that the zoom-in and back-off story is a myth. If you need your main subject(s) to have a given size (which is normally the case), there is no difference in DOF when zoomed in or zoomed out all the way. Only imager size (CCD, film, ground glass,..) and F-number play a role.

Rob Lohman · October 25th, 2004, 06:45 AM

It is true if you need to have your subject a given size. See the
following excellent article to learn all there is to know:

http://www.dvinfo.net/articles/optics/dofskinny.php

I was trying to express ways to play with the depth of field to
get an understanding. I did a poor job as Andre pointed out.

I've removed my incorrect line from the previous post, it read:

" Zoom in all the way to your subject (this might mean you need to move your camera back) "

Which as explained, is incorrect to help in DoF. It will help you
see the points Andre and the article make though.

October 25th, 2004, 04:40 AM	#1
Dario Corno Regular Crew Join Date: Sep 2004 Location: Turin (ITA) Posts: 30	Smaller DOF Hi averyone, first of all I want to apologize for my terrible english...then, on to the question. I have an XL1s camera, and I've fallen in love with it, I'm doing reflex photography since some years now, and whould love to achieve the same SMALL DOF I can get with my reflex camera on the Xl1s. I've tried the best setup with the XL1s in a very sunny day, but can't get that well "blurry" background I can get with the reflex lenses. Now I was thinking about an EF adater, will the f-stop of the EF lens be affected by the adapter (or camera ccd) ? if I buy a very light lens, with an high f-stop will it work on the XL1s the same as on the reflex camera ?? Thanks, and sorry for my english and my (maybe dumb) question. :D __________________ -- rIO.sK www.offiCineItalia.it

October 25th, 2004, 04:58 AM	#2
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	That will not work due to the magnification factor (7.2x). Sorry. You can get a bit smaller DoF by doing the following with the default lens on the XL1S. Open the iris as much as possible (f2.8 for example, which might mean you need to add ND filters [either onboard and/or external) Other than that you will need to get a true 35mm adapter to use true 35mm lenses. Basically their are two options. Buy or rent the P+S Technik mini35 (costs $10.000 to buy excluding lenses) or build your own (see our Alternative Imaging forum) __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

October 25th, 2004, 06:45 AM	#4
Rob Lohman RED Code Chef Join Date: Oct 2001 Location: Holland Posts: 12,514	It is true if you need to have your subject a given size. See the following excellent article to learn all there is to know: http://www.dvinfo.net/articles/optics/dofskinny.php I was trying to express ways to play with the depth of field to get an understanding. I did a poor job as Andre pointed out. I've removed my incorrect line from the previous post, it read: " Zoom in all the way to your subject (this might mean you need to move your camera back) " Which as explained, is incorrect to help in DoF. It will help you see the points Andre and the article make though. __________________ Rob Lohman, visuar@iname.com DV Info Wrangler & RED Code Chef Join the DV Challenge \| Lady X Search DVinfo.net for quick answers \| Buy from the best: DVinfo.net sponsors

October 25th, 2004, 06:21 AM	#3
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Rob, sorry but it has been repeated over and over again that the zoom-in and back-off story is a myth. If you need your main subject(s) to have a given size (which is normally the case), there is no difference in DOF when zoomed in or zoomed out all the way. Only imager size (CCD, film, ground glass,..) and F-number play a role.