Help with 20D and 50mm 1.8 Prime

Lloyd's · 11th December 2005

Hi all,

Need the advice of the more experienced old-timers here.

I just bought a 20D and a 50mm F1.8 Prime lens.

I was going thru the manual about the A-DEP Mode (pg.82), regarding holding down the shutter button halfway and press the Depth Of Field preview button to see the Depth Of Field. However when I did it, I don't see any difference at all to the screen through the view finder. Its like the button is completely useless and the button doesn't work at all!! I repeated the process a few times and nothing happened.

Was wondering if you guys had the same experience? Or perhaps some advice / explanation for me? As I do not have a normal zoom lens currently thus I cannot relate and compare if it was a case of faulty Depth Of Field preview button or just because I am testing it with a prime. Is the Depth of field preview button not applicable on a prime? But that doesn't make sense to me.

Any advice from the kind souls here will be much appreciated.

Many thanks in advance!!!

USM · 11th December 2005

What aperture are you using?

Try Av mode and use f22. Press the DOF preview button to see what's happening. After that, use f1.8 and repeat the process again. You should be able to see the difference.

solarii · 11th December 2005

Haha its not easy to see the difference on a dSLR with a 1.6x crop sensor. The focusing screen is just to small! I don't find the DOF preview particularly useful. Furthermore the bokeh produced by the 50/1.8 isn't very pronounced unless viewed on a screen, so its unlikely you'll see much change using DOF preview when u combine both factors.

DOF preview is definitely useful on medium and large format cameras with much larger focusing screens.

Lloyd's · 11th December 2005

Hi guys...

Got to the problem.

Many thanks for you replies...

Lloyd's of London

11th December 2005	#1
Lloyd's New Member Join Date: Dec 2005 Posts: 26	Help with 20D and 50mm 1.8 Prime Hi all, Need the advice of the more experienced old-timers here. I just bought a 20D and a 50mm F1.8 Prime lens. I was going thru the manual about the A-DEP Mode (pg.82), regarding holding down the shutter button halfway and press the Depth Of Field preview button to see the Depth Of Field. However when I did it, I don't see any difference at all to the screen through the view finder. Its like the button is completely useless and the button doesn't work at all!! I repeated the process a few times and nothing happened. Was wondering if you guys had the same experience? Or perhaps some advice / explanation for me? As I do not have a normal zoom lens currently thus I cannot relate and compare if it was a case of faulty Depth Of Field preview button or just because I am testing it with a prime. Is the Depth of field preview button not applicable on a prime? But that doesn't make sense to me. Any advice from the kind souls here will be much appreciated. Many thanks in advance!!!

11th December 2005	#2
USM Senior Member Join Date: Apr 2002 Posts: 13,880	Re: Help with 20D and 50mm 1.8 Prime What aperture are you using? Try Av mode and use f22. Press the DOF preview button to see what's happening. After that, use f1.8 and repeat the process again. You should be able to see the difference.

11th December 2005	#3
solarii Member Join Date: Oct 2005 Location: Bt. Timah Posts: 1,375	Re: Help with 20D and 50mm 1.8 Prime Haha its not easy to see the difference on a dSLR with a 1.6x crop sensor. The focusing screen is just to small! I don't find the DOF preview particularly useful. Furthermore the bokeh produced by the 50/1.8 isn't very pronounced unless viewed on a screen, so its unlikely you'll see much change using DOF preview when u combine both factors. DOF preview is definitely useful on medium and large format cameras with much larger focusing screens.

11th December 2005	#4
Lloyd's New Member Join Date: Dec 2005 Posts: 26	Re: Help with 20D and 50mm 1.8 Prime Hi guys... Got to the problem. Many thanks for you replies... Lloyd's of London