Light loss versus nice bokeh?

Toenis Liivamaegi · August 10th, 2006, 01:00 AM

I have Nikon D100, Conax RTS II Beattie and Canon EE-A here on my desk and neither of them doesn`t have any markings. All of those screens cover full 35mm frame.
All of those screens are frensel type focusing screens which doesnt require any additional optics (like PCX lens) in DOF adaptor design when camera is able to focus close enough to 35mm frame.

Ben Winter originally tested the Nikon D100 screen and that gave me an idea that maybe other modern (D)SLR`s have focusing screens with two layers too, one premanent in-camera layer with markings and another (interchangeable) screen without any markings.

Regs,
T

Mike Oveson · August 10th, 2006, 05:59 AM

Most interesting. I appreciate the information. Apparently I was misinformed about the Canon screen. Always wanted to give it a try but didn't want to waste my money if it wasn't free of markings.

Thomas Richter · August 27th, 2006, 12:19 PM

Ok, I bought the EE-S screen an tested it. Toenis, this is an awesome find, thanks so much in the name of the DOF DIY comunity!
Obviously I cannot speak for the comunity but I do strongly believe that this screen will help many of us.

My first tests yesterday and today suggest that the Ee-s is very good: Invisible fresnel, very small grain, good bokeh and, surprise, no excessive lightloss at all (the ligtloss in comparison to the EE-A can be neglected between F 1.2 and 2.0)

I'll now start a separate thread on this screen and how to combine it skillfully with an achromat or close up lens to form a static adapter easy to DIY.

I J Walton · August 27th, 2006, 12:32 PM

I have been looking for an affordable PLAIN focusing screen for sooo long. Thanks for pointing these screens out guys! I have found a place in England where I can buy them from quite cheap. I will get one and give it a try!

Thomas Richter · August 27th, 2006, 12:37 PM

Yes they are plain - and they may be among the best - even compared to the much more expensive models. But that will require some more testing than I did today to veryfy their "universal usefulness" ;-)

Ivan Brasen · August 27th, 2006, 01:11 PM

I'm not sure if it is image of real EE-S screen, but preview image on BH PhotoVideo have circle in middle of it. It's not real marking but its part of focusing screen.

http://www.bhphotovideo.com/bnh/cont...ist&sku=402221

I have something similar on my Minolta 5D/Sony Alpha focusing screen. It is almost invisible at f1.4-f2.0 but at f4.5 it is noticable even when focusing screen is vibrating.

some screenshots from my focusing screen at http://35mm.prozone.sk

So I'd like to ask..is your EE-S really "clean" or there is same circle in middle ?

Thomas Richter · August 27th, 2006, 01:42 PM

IF this circle only appears around f 4.5, it may be also present on the ee-s. However, using a f 1.8 lens I did not see anything that resembled a circle on the diffusion screen. Also, nothing could be seen looking at the screen with the naked eye. I did also move it over a lightbulb in the background (without lens) to look at the diffusion in a magnifying glass, but nothing appeared.

Unfortunately, it is quite possible that this circle is there at F 4.5. And, which is worse, I will now worry about it all week because next time I can test with F stop lower than 1.8 is next weekend. :-(

Although it may not be good news, thanks Ivan for pointing out a very important detail.

Toenis Liivamaegi · August 29th, 2006, 03:04 AM

Ivan, it`s not real image of the EE-S focusing screen on BH site.
Frensel rings on EE-S go all the way to the center not as shown on that image.

Older EOS screens had that problem as you pointed out, those didn`t have frensel in the middle so screens were absolutely clear in the centre - about 5mm in diametre.

I hope I can post some EE-A and EE-S footage soon as well as D100 and a clear Beattie must assemble our adaptor production prototype first.

Best regards,
Toenis

August 10th, 2006, 01:00 AM	#16
Toenis Liivamaegi Major Player Join Date: Nov 2005 Location: Tartu, Estonia Posts: 579	I have Nikon D100, Conax RTS II Beattie and Canon EE-A here on my desk and neither of them doesn`t have any markings. All of those screens cover full 35mm frame. All of those screens are frensel type focusing screens which doesnt require any additional optics (like PCX lens) in DOF adaptor design when camera is able to focus close enough to 35mm frame. Ben Winter originally tested the Nikon D100 screen and that gave me an idea that maybe other modern (D)SLR`s have focusing screens with two layers too, one premanent in-camera layer with markings and another (interchangeable) screen without any markings. Regs, T

August 10th, 2006, 05:59 AM	#17
Mike Oveson Major Player Join Date: Jan 2006 Location: Ogden, UT Posts: 349	Most interesting. I appreciate the information. Apparently I was misinformed about the Canon screen. Always wanted to give it a try but didn't want to waste my money if it wasn't free of markings.

August 27th, 2006, 12:19 PM	#18
Thomas Richter Regular Crew Join Date: Apr 2005 Location: Frankfurt, Germany Posts: 181	Ok, I bought the EE-S screen an tested it. Toenis, this is an awesome find, thanks so much in the name of the DOF DIY comunity! Obviously I cannot speak for the comunity but I do strongly believe that this screen will help many of us. My first tests yesterday and today suggest that the Ee-s is very good: Invisible fresnel, very small grain, good bokeh and, surprise, no excessive lightloss at all (the ligtloss in comparison to the EE-A can be neglected between F 1.2 and 2.0) I'll now start a separate thread on this screen and how to combine it skillfully with an achromat or close up lens to form a static adapter easy to DIY.

August 27th, 2006, 12:32 PM	#19
I J Walton Regular Crew Join Date: Aug 2005 Posts: 40	I have been looking for an affordable PLAIN focusing screen for sooo long. Thanks for pointing these screens out guys! I have found a place in England where I can buy them from quite cheap. I will get one and give it a try!

August 27th, 2006, 12:37 PM	#20
Thomas Richter Regular Crew Join Date: Apr 2005 Location: Frankfurt, Germany Posts: 181	Yes they are plain - and they may be among the best - even compared to the much more expensive models. But that will require some more testing than I did today to veryfy their "universal usefulness" ;-)

August 27th, 2006, 01:11 PM	#21
Ivan Brasen New Boot Join Date: Sep 2005 Location: Slovak Republic Posts: 9	I'm not sure if it is image of real EE-S screen, but preview image on BH PhotoVideo have circle in middle of it. It's not real marking but its part of focusing screen. http://www.bhphotovideo.com/bnh/cont...ist&sku=402221 I have something similar on my Minolta 5D/Sony Alpha focusing screen. It is almost invisible at f1.4-f2.0 but at f4.5 it is noticable even when focusing screen is vibrating. some screenshots from my focusing screen at http://35mm.prozone.sk So I'd like to ask..is your EE-S really "clean" or there is same circle in middle ?

August 27th, 2006, 01:42 PM	#22
Thomas Richter Regular Crew Join Date: Apr 2005 Location: Frankfurt, Germany Posts: 181	IF this circle only appears around f 4.5, it may be also present on the ee-s. However, using a f 1.8 lens I did not see anything that resembled a circle on the diffusion screen. Also, nothing could be seen looking at the screen with the naked eye. I did also move it over a lightbulb in the background (without lens) to look at the diffusion in a magnifying glass, but nothing appeared. Unfortunately, it is quite possible that this circle is there at F 4.5. And, which is worse, I will now worry about it all week because next time I can test with F stop lower than 1.8 is next weekend. :-( Although it may not be good news, thanks Ivan for pointing out a very important detail.

August 29th, 2006, 03:04 AM	#23
Toenis Liivamaegi Major Player Join Date: Nov 2005 Location: Tartu, Estonia Posts: 579	Ivan, it`s not real image of the EE-S focusing screen on BH site. Frensel rings on EE-S go all the way to the center not as shown on that image. Older EOS screens had that problem as you pointed out, those didn`t have frensel in the middle so screens were absolutely clear in the centre - about 5mm in diametre. I hope I can post some EE-A and EE-S footage soon as well as D100 and a clear Beattie must assemble our adaptor production prototype first. Best regards, Toenis