I received the microprism-only Brightscreen yesterday. Swapping the existing diagonal-prism with microprism-collar Brightscreen for the new one took but a moment.
Compared to the dual focussing aid version of the screen, the microprism-only version makes the finder look completely uncluttered and I prefer this look. I was interested to see if focussing accuracy would be less on a subject where the diagonal screen would allow a hight degree of certainty as to the difference between in-and out-of-focus and, as well, I wanted to reassure myself that some of the recent complaints about the screen not allowing accurate manual focus (compared to what AF could do with the same lens) could be duplicated.
I decided to use the APO-90 Summicron-R as the test, as its Depth of Field is very shallow when wide open. As well, I used the side of a shed at an angle, so I would be able to see where the in-focus zone was if, in fact, the area I focussed on was soft.
The first image is full frame: the side of a shed with a red mark on one of the protruding metal mouldings.
Edited by Kit Laughlin on Jan 04, 2006 at 07:28 PM GMT (Reason: wrong image!)
And now the crop of the centre area; you will see that the nail heads as well as the moulding itself and the red rectangle show that focus is perfectly achieved and (it seems to me) that the old one-third in front/two-thirds behind rule regarding the depth of the in-focus zone seems to hold here.
I shot the images a few times, deliberately going from well out of focus to in-focus and out again in the one direction, before reversing the action. All images were the same on inspection, so I processed the last one. All shots were off a tripod, using mirror lockup (which I have set on the Custom button for easy access. One day, Canon will put ML on a button—and the "Print" one seems like a good candidate!).
The microprism allows just as much accuracy as the diagonal prism, IMO. I find the large centre circle of the microprism (over half the vertical height of the finder) to be excellent, uncluttered, simple to use, and non-intrusive, composition-wise. Highly recommended.
Regards, kit
Edited by Kit Laughlin on Jan 04, 2006 at 07:29 PM GMT (Reason: wrong size image)
Edited by Kit Laughlin on Jan 04, 2006 at 07:30 PM GMT
Thank you for this review, Kit. I actually prefer the microprism spot center to the split-image with microprism collar. Is the one you tested the standard size or the larger 13mm microprism spot center? I am not sure if Brightscreen offers both sizes for the 5D.
Also, would this be the Canon screen or the Proscreen?
Kit; I received the p235 (d) for my Eos 5D the other day.
I have changed numerous screens in the past with no problems but I haven't managed to get the Brightscreen in properly...
It front focuses a bit, i.e. focus ends up behind the intented spot.
What can I do? I tried at least 7/8/9 times and can't get this one right.
On indoor shots I actually find it easier to use the generic Canon screen but I suspect the Brightscreen would work better for outdoor use, and especially for wides. I was surprised the Brightscreen was so dark outside the microprism collar and split. I often focus on the screen with the composition done so I don't always use the split/prism. This was a minus for me as well with the indoor darkening of the image.
I find the huge split screen somewhat cluttery together with the prism and the AF markers and maybe I should have gone for the prism only.
However, initial impression, thumbs down. I have 20/20 vision and usually manage all sorts of screens but I am perhaps spoilt by my old Contax screens (RX/RTSII and III, split screens and prism only screens) which were great in all conditions.
I've got the Microprism-only Proscreen coming. It will be interesting to see how well I can focus those German wides. No hyperfocus for his dude! I'm begining to enjoy shooting at wide apertures. Do you use any sort of eyepiece magnifier?
p.1 #11 · Microprism-only Brightscreen on Canon 5D
Butch; it is harder under certain light conditions with a 4.5 lens, that's for sure.
The microprism should still work very well, what you need to do is practise centering the eye when looking through the finder which should help eliminate the problem. In my experience the microprism works better than split image which has a tendency to black out with slower lenses and dull light but centering the eye is even more important with a split. I think your Nikkor 300/4.5 would be a pain under certain conditions.
p.1 #12 · Microprism-only Brightscreen on Canon 5D
Q.s in order, as I remember!
Henrik,
I found your comments about indoor vs. outdoor usability interesting, so this morning I decided to take a few images of a spirit level (incorporating a ruler) to test this. The light level was low (ƒ2 @ 1/6). Again, Apo-90, tripod and remote release. The DOF was shallow enought to be sure of the zone of focus, and I will post these four shots in a moment. I focussed on the "1" of the 12 on the rule.
I found the microprism-only screen is easier to focus accurately in really low light than the diagonal split. My reasoning here is that the diagonal is a compromise in most situations: if you are focussing on a vertical line, then a horizontal split is your friend, and vice versa for horizontal lines. In my first post I mentioned that the diagonal would be able to be used in both situations, but that the geometrical disadvantage of the 45 degree diagonal (potential lower degree of accuracy in certaintly of focus vs. vertical or horizontal) would not be a problem.
What I have found, though, in the last few weeks was what Guy mentioned (staring at the split too long) was indeed the case. In fact my eyesight is good enough and the split was aligned well enough for me to find myself looking at the split—but only that part that appeared in the tiny centre AF rectangle! And on a product shoot where I had to scrim down the light from the flash box (and hence the modelling light) and I was shooting aubergine (eggplants) and black olives, I found myself using the prism collar because the split-prism fine lines were invisible against black. I found myself using the collar every time in difficult light, and this was the reason I wanted to test the all-microprism design.
JJL: I tried the magnifier after reading your post, and I will show the results below. In short, the prism-only finder seems to be easier to use WITHOUT the magnifier. This is curious, and the possible reasons might shed some light on Henrik's problem—I found that the 2.5 X magnifier definitely does slightly forward-focus—but here the perception of in- and out-of-focus is being altered by the necessity of readjusting the finder itself (after re-setting the diopter adjustment). This is necessary if your required diopter adjustment is more than 4 clicks (you find that if you need more than that on the finder alone, you will not be able to correctly focus the magnifier without resetting the diopter adjustment closer to the zero point; it just does not have enough adjustment built in). My feeling is that the two optics are affecting each other, producing the very slight forward focus (which I was sure was focussed on the "1" of the 12).
My finding is that on macro shots, the standard finder plus Brightscreen is more accurate more often than the Brightscreen plus magnifier finder. This is a surprise (and a blessing, if it's real) because fitting and defitting and readjusting the dioptre is a bit of a pain.
Michael: thanks for that review
Butch: with slow lenses, the microprisms stay usable longer (slower ƒ-stops) than the split. I suggest that the prism-only version of the Brightscreen will suit you better.
Personally, I am going to use only the prism circle version only from now on, and will see if there's a four-line fine vertical and horizontal grid available (big architectural project coming up).
Here's the normal finder-only result. First image FF; next is crop, etc.
cheers, kit
Edited by Kit Laughlin on Jan 05, 2006 at 11:20 AM GMT (Reason: typo)
p.1 #15 · Microprism-only Brightscreen on Canon 5D
And last the crop:
Henrik—can you replicate this setup or something close, and post your results? Don't forget to fine-tune the diopter with the new screen in, even if you have 20/20 vision: the screen might change that, by a tiny amount. For me, getting that spot-on fixed my apparent focussing problem. Alternatively, could you duplicate the same test, but with the original finder screen? That might eliminate a variable or two.
You can see from here that the magnifier seems to produce a tiny forward focus—but I can't be certain that this is not operater error. I am incliing to the multiplication of optical effects, though. JJL might like to comment on that. cheers to all, kit
p.1 #16 · Microprism-only Brightscreen on Canon 5D
Kit: phew! You must really be training your eyes on that APO 90. That's shallow!
I agree that the diagonal split can be hard at times, if you focus on something that has an angle to it (like a shelf at an angle) getting that diagonal in can be hard and sometimes slightly off.
After quite a few changes between the old screen and the Brightscreen the results are fairly consistent; on the Canon screen I nail it, on the Brightscreen actual focus ends up a cm or so behind where I focus - that would be just under half an inch for our american friends. ;-).
Changing the diopter setting was tedious; my eyes got used to compensating so after a while I had a hard time finding a "very best" setting. I do agree that the diopter setting can shift the focal point a little bit. I did try several minute changes but no luck in nailing the ruler with the Brightscreen. I tried the split, the prism and the screen outside the prism.
I'll try and do it again tomorrow with some sleep in the system, I just erased the files from the camera before logging in to FM so no evidence at present - I'll try and get some testshots redone tomorrow or the day after.
p.1 #18 · Microprism-only Brightscreen on Canon 5D
That was the 50 Summicron—on a set of bellows!
just for fun! cheers, kit
PS: you are NOT getting the Apo-90 back, Guy, ya' hear me?
soon, kit
Jan 04, 2006 at 11:23 PM
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p.1 #19 · Microprism-only Brightscreen on Canon 5D
I just ordered the pro microprism today. I also made one of those 1.25X eyepiece magnifiers with the Nikon DK17m. I can understand where the Angle Finder C can get dicey with its mirror, and adjustable focus as well. I did the focus test with my Angle Finder C and the Canon 50/2.5 macro a while back to make sure my EcB was jiving with my sensor plane of focus, and it looked OK to me, but that was with a f2.5 lens. I will try again with combinations of eyepieces and magnifiers using my 85/1.2 when the screen arrives and report back.
p.1 #20 · Microprism-only Brightscreen on Canon 5D
Asked Brightscreen and here is the reply:
"The only known possibilities at this time is #1 the screen being seated not
properly and or with the screen carrier being bent or miss-aligned #2 could
be a result of a lens adapter being miss-machined. #3 could be the lens
alone or in combination with an adapter. The only other remote possibility
could be in the production QC of some particular cameras."
So, I need to check the variables thoroughly I guess.
The thing that is odd is just the fact that the Canon screen works fine.
