p.13 #1 · Microprism-only Brightscreen on Canon 5D
Viktor
I talked to Jim last week and he told me 14-21 days for production run of the new 13mm prism screens for R9/DMR. He apparently has quite a number of orders so you may want to get yours on order soon
Woody
May 18, 2006 at 10:12 AM
jjlphoto Offline • • • • • [X]
p.13 #2 · Microprism-only Brightscreen on Canon 5D
gogopix wrote:
100 x seems bad. For wide open say 1.4 80mm, that is only 25ft!. This could lead to being at hyperfocal point, not infinity, if I remembr my optics right
Correct!
That"s the whole point of the Harold M. Merklinger link I posted. If your technique is to rely on the hyperfocal principle to bring in those small distant things, you will simply not be able to obtain the high performance that your lens was designed to deliver.
p.13 #3 · Microprism-only Brightscreen on Canon 5D
carstenw wrote:
I am one of those Canon orders. I am generally happy with the service, but a little miffed that they took the payment immediately, but took so long so send. I had a shipment come in yesterday, and took a half day off from work to pick it up early, anticipating that it would be the Proscreen, or at least the 80 Lux. Turned out to be some printer ink cartridges and paper, as well as some old LFI editions :(
Btw, I noticed a couple of days ago that I can't get true infinity with my 90 Cron. I will try rotating my adapters around, but I may need to look at something better than the F/S adapters. It is very close, as I can focus at about 30-40m, but not on the horizon. I read somewhere that Leica uses 1000 (or was it 10000?) times the focal length as infinity. I think I read that Canon uses 100... Can anyone confirm these numbers?...Show more →
it might be 1000 and 10000... I have to find those links...
Anyway, my Proscreen for my 5D arrived, so now I have to figure out which lenses to keep and which to sell. I am currently leaning towards selling the 90/2 and keeping the 80/1.4 and 90/2.8. That would seem to make sense, but first I have to confirm that I can focus properly, and that I can get infinity focus. I am pretty sure right now that I don't get infinity focus on all my lenses. I will try to rotate the adapters and see how many lenses I can get sorted out, and then buy higher quality adapters for the rest. Does anyone have any tips on Novoflex vs. CamQuest (?) adapters?
The Proscreen came with a little metal shim. I tried first without, but found that I could only get exact focus by coming from the near side, and stopping as soon as the shimmer cleared up, but very close. Otherwise I would focus too far, consistently. With the shim in I can come from infinity and stop when the shimmering stops, but with more of a gap... Hard to explain, but that works much better for me, and so far I am getting good results like that with the 80/1.4, 90/2.8 and 50/2. I have to test all the lenses, but I think my keeper ratio is about to improve.
p.13 #4 · Microprism-only Brightscreen on Canon 5D
Hello Woody
Proscreen i order May 9 right after Thumbs up from Guy and Kurt. My only issue is the trip I am starting on this Friday 26th.9th+14=23rd soooooo
Most recent shots with smaller prism only actually misleading esp if there are big contrast differnces in the sceen. I was hoping the larger micrprism would be more definitive in focus
p.13 #5 · Microprism-only Brightscreen on Canon 5D
I am having some trouble with my Proscreen, or at least, with some component of my system. Most of the time, and almost all of the time in real-life situations, I focus fine, but then every once in a while I get into a situation where I can't seem to get it to work right, and have to focus by trial-and-error. Once recently it was he 50 Summicron, which is otherwise dead-reliable. I was taking a pictures of a scooter from low down, perhaps at a distance of 1.5m, and I had to focus so far in front of where I wanted to be sharp that the microraster was not clear any more. Has anyone had anything like this happen? I don't know when it happens, but I am very leery now. I might try a couple of these focusing chips.
p.13 #6 · Microprism-only Brightscreen on Canon 5D
So what are the updates? I'm contemplating buying Proscreen #2 to improve manual focus of super-tele (500mm/F8 reflex lens) on EOS 5D,.
Also, can you please share with me your AE experience with this Proscreen? Did you have to set Custim Function 00 to something other than 0 to make AE work properly? Did it suffice?
I got a recommendation to set CF.00 to 2 for Proscreen #2 (p232) on EOS 5D. I can't do it until I receive my new screen. Anybody tried it yet?
Any experience with slow (F8+) long-focal-length glass and Proscreen?
Thanks!
Edited by Mouse07410 on Jun 15, 2006 at 10:48 AM GMT
p.13 #7 · Microprism-only Brightscreen on Canon 5D
My Proscreen starts getting darker at f/4 and is pretty dark at f/5.6. I am not sure if using such a screen for f/8 lenses would be easy. I would guess that a Brightscreen matte screen might be better. Can someone confirm?
p.13 #8 · Microprism-only Brightscreen on Canon 5D
I'm willing to bet that matte won't be easy either - the main Ee-A screen that Canon ships with 5D is matte, and manual focusing is not easy at all with f/8+.
But my bigger concern is how badly AE is screwed by introduction of a different screen, and whether a reliable remedy (short of buying a standalone spot-meter) is available.
p.13 #9 · Microprism-only Brightscreen on Canon 5D
The screen which ships with the 5D is meant for clarity, not focusing, because of AF. A matte screen meant for focusing should be better.
Autoexposure is often quite far off in my experience, even at lower apertures. I usually use spot metering, set the exposure, shoot a shot, correct, and shoot again. I use manual, and just set the exposure with the shutter speed, as I usually shoot wide open.
p.13 #10 · Microprism-only Brightscreen on Canon 5D
Mouse:
On the Canons, the AF sensor is behind the mirror, so screens do not affect the AF. The mirror is a beam splitter, where some light goes to the prism, some goes straight through to the AF sensor in the mirror box.
The metering in the Canons is in the prism area, so screens do affect metering.
p.13 #11 · Microprism-only Brightscreen on Canon 5D
But my bigger concern is how badly AE is screwed by introduction of a different screen, and whether a reliable remedy (short of buying a standalone spot-meter) is available.
I use a KatzEye split prism screen in the Canon 20D and have the same exposure problem. Spot metering is the most affected with a screen change, center weighted average the least affected.
With a Canon lens, I just have to use center weighted avg and set -1 exposure. It is then very accurate.
With a manual focus lens, this is a different story. I have done tests with several lenses using Kodak gray cards to fill the entire view area and compared meter readings. They are all over the place as aperture changes. The metering usually changes most significantly from f2.8 to f5.6.
If you use an autofocus chip, it changes metering again because it is telling the camera the aperture.
If I use a Zeiss 85mm 1.4 with autofocus chip and Katzeye screen and center weighted avg, it meters correctly at f1.4 and f2. I think I am going to make a small list for myself on where each lens meters correctly and try to work around the problem. As long as I am shooting flowers or landscapes it is not so big a problem.
p.13 #12 · Microprism-only Brightscreen on Canon 5D
I see - my fears have materialized :-). The metering will be screwed.
1. For Canon native AF ("L") lenses with decent apertures, probable remedy is to use center-weighted avg and dial in -1 EV.
2. For MF fixed-aperture slow lenses - experiment and see.
3. Metering screw-up is only with lenses that meter wide open but take the shot stopped-down. Is this correct?
Two things are still unclear to me:
A. Did anybody try to change CF.00 setting (say, to 1 instead of the default 0) and see if it took care of AE offset?
B. Once the picture is brought in focus - the microprism should be pretty much as transparent as the rest of the screen, right? So if I meter the exposure then - it should be the closest to the "norm" expected by the metering firmware? And thus work with spot-metering, matrix evaluation, etc.? What is the difference between this Brightscreen and say Ee-A from metering point of view when the subject is in perfect focus?
p.13 #13 · Microprism-only Brightscreen on Canon 5D
1. For Canon native AF ("L") lenses with decent apertures, probable remedy is to use center-weighted avg and dial in -1 EV.
This works for my Katzeye split prism screen wit OptiBrite treatment. Others may vary.
3. Metering screw-up is only with lenses that meter wide open but take the shot stopped-down. Is this correct?
If there is an aperture that meters correctly in your lens-screen combination, meter at that aperture and then manually set the aperture and shutter shpped for your shooting aperture. If your shooting aperture actually meters correctly, you have the best instance.
B. Once the picture is brought in focus - the microprism should be pretty much as transparent as the rest of the screen, right? So if I meter the exposure then - it should be the closest to the "norm" expected by the metering firmware? And thus work with spot-metering, matrix evaluation, etc.? What is the difference between this Brightscreen and say Ee-A from metering point of view when the subject is in perfect focus?
No, the focus does not change how much light the screen transmits for metering. The things that affect metering are the focus screen, lens characteristics (aperture and possibly others) and the compensations (or lack thereof) Canon has built into the camera when it has an "unkown" lens. You have to experiment to see what works.
Just use a scene indoors and meter with different different lenses and modes and see what the pattern is for your equipment.
p.13 #14 · Microprism-only Brightscreen on Canon 5D
robsteve wrote:
Mouse:
On the Canons, the AF sensor is behind the mirror, so screens do not affect the AF. The mirror is a beam splitter, where some light goes to the prism, some goes straight through to the AF sensor in the mirror box.
The metering in the Canons is in the prism area, so screens do affect metering.
p.13 #15 · Microprism-only Brightscreen on Canon 5D
rgallie wrote:
I use a KatzEye split prism screen in the Canon 20D and have the same exposure problem. Spot metering is the most affected with a screen change, center weighted average the least affected.
With a Canon lens, I just have to use center weighted avg and set -1 exposure. It is then very accurate.
With a manual focus lens, this is a different story. I have done tests with several lenses using Kodak gray cards to fill the entire view area and compared meter readings. They are all over the place as aperture changes. The metering usually changes most significantly from f2.8 to f5.6.
You might want to close the viewfinder shutter on the body so that stray light coming in from the eyepiece is not part of the problem. However, in general, I concur that AE is affected by the screen(s) used
Woody
If you use an autofocus chip, it changes metering again because it is telling the camera the aperture.
If I use a Zeiss 85mm 1.4 with autofocus chip and Katzeye screen and center weighted avg, it meters correctly at f1.4 and f2. I think I am going to make a small list for myself on where each lens meters correctly and try to work around the problem. As long as I am shooting flowers or landscapes it is not so big a problem.
p.13 #16 · Microprism-only Brightscreen on Canon 5D
Mouse07410 wrote:
So what are the updates? I'm contemplating buying Proscreen #2 to improve manual focus of super-tele (500mm/F8 reflex lens) on EOS 5D,.
Also, can you please share with me your AE experience with this Proscreen? Did you have to set Custim Function 00 to something other than 0 to make AE work properly? Did it suffice?
Anybody had experience with slow (F8+) long-focal-length glass and Proscreen?
Thanks!
I use the Ec-B split and Ec-A micro prism Canon screens on a fixed f/6 600 mm tele and to me I don't see that dark is an accurate description of the prism functioning. Sure it may cut a little light but to me the big issue is eye alignment with the viefinder becomes more critical with the slower focal ratio. If your eye is aligned exactly then the split prism is evenly illuminated. If the eye is a little off centre then there is blacking of the prism area.
Alignment of the eye seems less critical with faster lenses. Does anyone else find this?
p.13 #17 · Microprism-only Brightscreen on Canon 5D
Craig, thank you! A very interesting and useful observation! When the screen arrives, I'll experiment with eye alignment and report my results. (I only wish there was a Canon-made microprism focusing screen for 5D - so I didn't have to muck with the metering.)
p.13 #18 · Microprism-only Brightscreen on Canon 5D
craig_oz_land wrote:
I use the Ec-B split and Ec-A micro prism Canon screens on a fixed f/6 600 mm tele and to me I don't see that dark is an accurate description of the prism functioning. Sure it may cut a little light but to me the big issue is eye alignment with the viefinder becomes more critical with the slower focal ratio. If your eye is aligned exactly then the split prism is evenly illuminated. If the eye is a little off centre then there is blacking of the prism area.
At f/5.6, if my eye is exactly centered, there is a clear area. At f/6.8 it is almost clear, and I can still focus, although there is a small amount of guesswork in it. At f/8 it is getting pretty bad, and there is never a clear area in the middle at all, and each microprism triangle is about half black all the time. This is just in testing the different apertures on a Leica 90 Elmarit.
Alignment of the eye seems less critical with faster lenses. Does anyone else find this?
Yes, although I am not sure if it is perceptual rather than factual? It might be interesting to focus with the eye off-center, with a fast lens wide-open, and compare with a centered eye, for focusing accuracy...
p.13 #19 · Microprism-only Brightscreen on Canon 5D
It may be because I shoot Raw only, but I have not noticed any great change in metering with the Proscreens in both my cameras. I use centre-weighted for most work.
If I am shooting for exposure blending, then a completely different story: I use a Pentax analogue Spotmeter from my film days, and expose for the various zones.
One member here did tell me that a grid-matte screen only was better for his slow (ƒ8) lenses, and that may be the better option that centreing the eye, if that's a problem.
Carsten: with fast lenses, off-centre eye placement makes no difference to focus, in my experience. It makes every difference for slow lenses, though! cheers, kl
p.13 #20 · Microprism-only Brightscreen on Canon 5D
I also shoot raw only, and notice quite severe problems. Sometimes, as with the red bicycle photo, if I meter wide open, and then stop down a couple of stops, the meter will move down 4-5 stops! It is usually fairly accurate wide open, but not lower down. It may be because of the blackening of the prisms at higher apertures, in fact, since the meter is on the other side of the focusing screen. I use spot, always.
