Just got the Katz Eye split prism focusing screen for my 30D

[fuzzybabybunny]

http://www.katzeyeoptics.com/i...-Screen--prod_30D.html

I got the screen with the additional Opti-Brite treatment from someone on FredMiranda for $100 shipped/insured/paypaled.

Installation took a while because the official instructions actually had me installing the screen backwards, but eventually I figured it out.

Some of my lenses that I've tested so far are focusing off to some degree except for the Sigma 10-20mm, which is understandable because it's got such a wide DOF to begin with. For each lens I take a shot with AF, pressing the button numerous times before the shot to make sure that the AF lock is as spot on as it's going to be. Then I take another shot manually focusing with the Katz Eye.

Canon 50mm f/1.4: very very close to spot on sharpness, but at f/1.4 very very close sometimes doesn't cut it. Took a picture of a Logitech logo about the size of a human eyeball and MF was spot on while AF had half of the logo blurred with the other half in focus.

Sigma 30mm f/1.4: less close than the 50mm. Not nearly close enough for work at greater than f/2. This thing is pretty damned sharp at f/1.4, but it doesn't show with AF because it's off.

Tamron 17-50mm: very very close like the Canon 50mm. Because it's f/2.8, being off by this tiny bit is not perceptible in the image, unlike the Canon at f/1.4.

Sigma 18-200mm: spot on

Sigma 100-300mm: haven't been able to test yet

Sigma 50-500mm: haven't been able to test yet

 

[GoingUp]

How does this thing work and let you know youre in focus?

 

[ElFenix]

Originally posted by: Gobadgrs
How does this thing work and let you know youre in focus?

same way cameras did before autofocus

 

[fuzzybabybunny]

Originally posted by: Gobadgrs
How does this thing work and let you know youre in focus?

This is what you see in the viewfinder.

http://www.thezeal.com/blog/wp...lossary/splitprism.gif

Notice the circle in the middle, and how it's cut in half with the horizontal line.

Imagine that you're focusing on a straight vertical tree branch. You center the circle on the branch, and if the branch is out of focus, it will appear to be split where the horizontal line cuts the circle in half. To get the branch in focus, you have to manually focus until the image in the upper half of the circle and the image in the lower half of the circle join up, and no longer appear to be split.

Out of focus, the branch appears to be split. In focus, the branch appears to be whole.

I noticed on a few of my lenses that even with the AF saying that it was in focus, the prism image was still a little bit split, so I knew that the AF was off.

 

[Shimmishim]

if the AF is off, is that a lens issue or a camera issue? i see the results are varying amongst your lenses so I'm guessing it's dependent on the lens...

could you send your lens to canon or sigma and get the AF mechanism tweaked or is this small amount of error something you can live with?

 

[randomlinh]

hrm. let us know how it effects metering. I really want to get one with my 20D, but it's a bit of moola and I don't want to break it trying to swap it out, heh. But MF is such a chore... I'm not sure I'll ever be happy unless I get a full frame dslr.

 

[Heidfirst]

Originally posted by: Shimmishim
if the AF is off, is that a lens issue or a camera issue? i see the results are varying amongst your lenses so I'm guessing it's dependent on the lens...

it can be either

could you send your lens to canon or sigma and get the AF mechanism tweaked

again, either (at least in the UK).

 

[fuzzybabybunny]

Originally posted by: Shimmishim
if the AF is off, is that a lens issue or a camera issue? i see the results are varying amongst your lenses so I'm guessing it's dependent on the lens...

could you send your lens to canon or sigma and get the AF mechanism tweaked or is this small amount of error something you can live with?

I'm thinking that in my case it's predominantly a lens issue. Although I suppose that it could be the camera issue in some cases.

Yes, you can definitely send your lens into Canon or Sigma or Tamron for focus calibration, but it's ENTIRELY up in the air whether they'll do a good job of it or not. I've heard countless stories of people sending their lenses in for calibration and the lenses come back still not focusing right. I think Sigma tends to do this all the time. Not sure about Canon or Tamron.

The small amount of error is something I can live with for now because I don't really want to spend money and time to get my lens tweaked (and then maybe find out that it wasn't tweaked right). If I find it's focusing badly I'll just manually focus it now that I have a good way to do it.

 

[corkyg]

Very interesting, Fuzzy. I changed the focusing screens in my 5D in order to correct a chronic vision problem. All my landscapers and distance shots were off by a minus three degrees. So, I installed a gridded screen (from Canon (Ee-D) and it solved the problem.
Ee-D
They also have a "Super" focusing screen (Ee-S) available, but it is not a split prism. I can see a real use for the Katz Eye screen with macro work and fast lenses with shallow DOF.

 

[fuzzybabybunny]

Originally posted by: randomlinh
hrm. let us know how it effects metering. I really want to get one with my 20D, but it's a bit of moola and I don't want to break it trying to swap it out, heh. But MF is such a chore... I'm not sure I'll ever be happy unless I get a full frame dslr.

Aye, I'll take note on the metering next time I go out and shoot, although I don't think it'll affect it too much (+/- 1/3 EV at the max methinks).

Yeah, I know what you mean. I actually broke off a tiny little plastic tab on the stock Canon screen when I took it out. It should still go back in perfectly fine though and sit tight because there are other tabs holding it in place as well as a metal frame that puts pressure on it.

As far as breaking the Katz Eye, I don't think it's possible unless you really screw things up. The only thing that I can think of is you could scratch it if you're not careful or get dust on it if you don't take care to clean it with a lens cloth. Swapping in and out takes literally 2 minutes.

And yeah, MF is definitely a chore with these 1.6/1.5x cameras. Maybe I'm off my rocker, but I feel like the viewfinder on Nikon APS-C cameras are noticeably bigger than Canon APS-C cameras, and the viewfinder on the Nikon D3 is bigger and brighter than even a Canon FF camera. Although to be fair I think that even if I did have a FF camera I'd still install a KatzEye, if only to have something solid to fall back on should the AF not be up to snuff. I don't like the "this LOOKS in focus so I guess it's in focus." I prefer the "I KNOW this is in focus because there's no split."

Yes, I got to touch and look through a D3 over my winter break. It was heaven.

 

[fuzzybabybunny]

Originally posted by: corkyg
Very interesting, Fuzzy. I changed the focusing screens in my 5D in order to correct a chronic vision problem. All my landscapers and distance shots were off by a minus three degrees. So, I installed a gridded screen (from Canon (Ee-D) and it solved the problem.
Ee-D
They also have a "Super" focusing screen (Ee-S) available, but it is not a split prism. I can see a real use for the Katz Eye screen with macro work and fast lenses with shallow DOF.

Definitely. I did a small amount of macro with this thing and it's great at normal magnification ranges, like from 0.5x to 2x. Beyond that, like 5x, 10x, etc. (like what you get with a reversed wide angle), the degree of displacement of the split prism is too small to tell whether something is in focus or not. The DOF at these levels are all less than 1 mm, so it's extremely easy to go completely out of focus and not even see a split.

These split screens are best for zoning in on perfect focus. This means that the object has to already be somewhat close to perfect focus for you to notice the split. With high magnification macro, "somewhat close" is hard to get. It's usually either entirely out of focus or in focus.

 

[randomlinh]

Originally posted by: fuzzybabybunny
As far as breaking the Katz Eye, I don't think it's possible unless you really screw things up. The only thing that I can think of is you could scratch it if you're not careful or get dust on it if you don't take care to clean it with a lens cloth. Swapping in and out takes literally 2 minutes.

And yeah, MF is definitely a chore with these 1.6/1.5x cameras. Maybe I'm off my rocker, but I feel like the viewfinder on Nikon APS-C cameras are noticeably bigger than Canon APS-C cameras, and the viewfinder on the Nikon D3 is bigger and brighter than even a Canon FF camera. Although to be fair I think that even if I did have a FF camera I'd still install a KatzEye, if only to have something solid to fall back on should the AF not be up to snuff. I don't like the "this LOOKS in focus so I guess it's in focus." I prefer the "I KNOW this is in focus because there's no split."

Yes, I got to touch and look through a D3 over my winter break. It was heaven.

Not too worried about breaking the katz eye, it's the $500 dSLR I don't want to botch Like you know, somehow jab a hole through the sensor, heh.

And yes, I almost switched to a D70/D80. I found their viewfinders to be amazing. Even the K10D I was considering. All far better than the canon stuff IMO. But.. alas, I could not pass up an almost free upgrade to a 20D from a rebel.. and well, just bought a new furnace... sooo.. katz eye for my birthday maybe, haha

 

[ElFenix]

Originally posted by: fuzzybabybunny
Maybe I'm off my rocker, but I feel like the viewfinder on Nikon APS-C cameras are noticeably bigger than Canon APS-C cameras

for the same magnification anything in a nikon/sony/pentax viewfinder will appear larger than in a canon viewfinder. it's the smaller canon sensor that does it.

the 40D's sensor is 328.59 mm sq. it's .95 magnification and .95 frame coverage, hich makes the resulting image 296.53 sq mm. the mirror reflects 60% of the light onto the focusing screen, the other 40% is used for AF (which is why manual focus film bodies have really bright finders).

the D300's sensor is 372.88 mm sq. that's 13.5% larger. the magnification is lower than the 40D, at .94, but that isn't enough to overcome the larger sensor. also, the frame coverage is 100%. so the resulting image is 350.51 sq mm. that's 18.2% larger.

the D80's sensor is also 372.88 mm sq. it also has .94 magnification, but it only has .95 frame coverage. that'll serve to make things a little more even with canon, but not that much. it's finder appears to be 332.98 sq mm. that's 12.3% larger.

 

[soydios]

Originally posted by: ElFenix

Originally posted by: fuzzybabybunny
Maybe I'm off my rocker, but I feel like the viewfinder on Nikon APS-C cameras are noticeably bigger than Canon APS-C cameras

for the same magnification anything in a nikon/sony/pentax viewfinder will appear larger than in a canon viewfinder. it's the smaller canon sensor that does it.

the 40D's sensor is 328.59 mm sq. it's .95 magnification and .95 frame coverage, hich makes the resulting image 296.53 sq mm. the mirror reflects 60% of the light onto the focusing screen, the other 40% is used for AF (which is why manual focus film bodies have really bright finders).

the D300's sensor is 372.88 mm sq. that's 13.5% larger. the magnification is lower than the 40D, at .94, but that isn't enough to overcome the larger sensor. also, the frame coverage is 100%. so the resulting image is 350.51 sq mm. that's 18.2% larger.

the D80's sensor is also 372.88 mm sq. it also has .94 magnification, but it only has .95 frame coverage. that'll serve to make things a little more even with canon, but not that much. it's finder appears to be 332.98 sq mm. that's 12.3% larger.

Yep, that's exactly it. I have an ancient yet still perfectly functional Nikkormat FTN, and that viewfinder is big and bright, with a proper split-prism. That camera shows just how long Nikon has been around: mechanical 1/4000s shutter, 60/40 center-weighted light meter, and everything is still calibrated.
And the cool part is that the 50/1.4 and 135/3.5 pre-AI lenses that came with it mount just fine on my D50!

 

[corkyg]

Just got this response from Katz:

Thank you very much for your inquiry. Unfortunately, we are not able to support the Canon 5D at this time. The 5D is a model we would like to support, but current technical limitations prevent us from making screens for this camera and it is unknown if we will support the 5D in the future. Work is ongoing, but no short term solution is apparent. I will add your name to the interest list for the Canon 5D and you will receive updates if/when more information becomes available. I'm sorry we can't meet your current need, but if I can be of any other service, please feel free to ask.

So, I guess I'll just go with the Ee-S precision screen from Canon via B&H.

 

[fuzzybabybunny]

Originally posted by: corkyg
Just got this response from Katz:

Thank you very much for your inquiry. Unfortunately, we are not able to support the Canon 5D at this time. The 5D is a model we would like to support, but current technical limitations prevent us from making screens for this camera and it is unknown if we will support the 5D in the future. Work is ongoing, but no short term solution is apparent. I will add your name to the interest list for the Canon 5D and you will receive updates if/when more information becomes available. I'm sorry we can't meet your current need, but if I can be of any other service, please feel free to ask.

So, I guess I'll just go with the Ee-S precision screen from Canon via B&H.

Haoda makes a split prism screen for the 5D:

http://haodascreen.com/Canon5D.aspx

 

[corkyg]

Originally posted by: fuzzybabybunny[/bHaoda makes a split prism screen for the 5D:
http://haodascreen.com/Canon5D.aspx

Thanks, Fuzzy! A Haoda is on the way. Will put that in the 5D used with the 50mm f/1.2 lens. Focus is very critical there due to the very shallow DOF at full aperture.