MF Focus Screen Questions (Canon, Haoda, Katz, eBay)

I keep reading that a focus screen will be dark in low light (understood) and slow apertures. All of my lenses are F2.8 and faster (except with a TC attached). Question is, will I be able to use a Canon EF-S focus screen no problem? Why do I see people say they have issues with f16 and f22 when our lenses don't stop down until we press the shutter?

What if I'm outside in great light and my TC attached (yielding F4 and F5.6 max apertures)? Will I still be able to use the EF-S focus screen?

I'd love to get a Katz Eye one, but I can't justify $160 to $205 for a focus screen... not yet. I've also considered toying with the eBay one for $35, but then again that $35 could have gone into the Katz Eye.

So, really my choices are
- Canon EF-S
- Haoda (which I can't seem to find one for a 40D on their site)
- Katz Eye with Optibrite.

I can’t comment on the EF-S or Hodia screen as I have never really used them, but I do that the Katz screen with optibright. It has no problems with any of my lenses (5.6 max ap. On the 400) and remains bright and easy to focus. One thing though. I have noticed that the screen is very touchy to eye misalignment. If your not perfectly centered you’ll see ½ of the split screen go dark even a f/2.8. It’s a great tool to keep your eye alignment just right. Supposedly if your shooting at a high aperture and you press the DOF button, you’ll see the screen blacken at f/11 or higher, but I never use that button so it’s not an issue for me.

If you have fast lenses, Haoda split prism focusing sceen works well.
I used to have it on my XT and I really liked it..

I only have 2.8+ lenses so I'm not much help in regard to the dimming question, but I had the ebay screen in my 350D and it did the job for me. My fiancee has the camera now and the screen is still in, she doesn't have any problems with it either. My eyes work MUCH better with the slightly larger 30D VF, so I haven't gotten around to replacing the screen in that camera, it did make a substantial difference for me with the 350D though.

drPheta wrote in post #5642876
Why do I see people say they have issues with f16 and f22 when our lenses don't stop down until we press the shutter?

The real problem is with slow lenses with teleconverters. An f/5.6 lens on a 2x teleconverter has a maximum aperture of f/11.

I have a Haoda 2nd-generation screen, and my lens is f/4-5.6. At the f/4 end there is no problem at all. At the f/5.6 end I have to take a moment to get my eye positioned in order to keep the split image circle from experiencing partial blackout. Similarly, the microprism collar is difficult to use at f/5.6 because I have to position my eye "just so" to get any one area of the collar working, and it's not possible to use the whole collar at once at f/5.6.

Nevertheless, I wouldn't want to go back to the standard screen (I use manual focus about 90% of the time).

Very bottom of this page.

Another option is the Hong Kong-based FocusingScreen.com (select your local currency in the left column). I've never used them, and haven't heard much from anyone who has. But then, I've never heard anything bad about any supplier (including the eBay ones). Just heard a lot of good things about both Haoda and Katz Eye.

drPheta wrote in post #5642876
I'd love to get a Katz Eye one, but I can't justify $160 to $205 for a focus screen... not yet. I've also considered toying with the eBay one for $35, but then again that $35 could have gone into the Katz Eye.

So, really my choices are
- Canon EF-S
- Haoda (which I can't seem to find one for a 40D on their site)
- Katz Eye with Optibrite.

Something else to keep in mind, about using Haoda or Katz Eye screens, is that while Canon includes a metering correction for specific Canon screens, there is no correction provided for non-Canon screens. The Haoda and Katz eyes might be suitable for someone using Evaluative metering only, but spot and partial metering can be erroneously biased by 2-3EV when the Haoda/Katz Eye are in place and the lens is slower than f/2.8...posting on POTN corroborates this metering error!

Yeah, I know about the metering discrepencey. But, that's something can cope with using the histogram. I just wish I could MF a lot easier. I learned with a Pentax K100 a while back and MFing was so much easier then.

Use either Evaluative or CWA and there will be no problems with metering.

drPheta wrote in post #5643594
Yeah, I know about the metering discrepencey. But, that's something can cope with using the histogram. I just wish I could MF a lot easier. I learned with a Pentax K100 a while back and MFing was so much easier then.

But if you are shooting in a high paced environment with changing light, dependence on the histogram simply to get the exposure in the ballpark, is not a viable approach! It might be fine when you have the time, but NOT when time is precious.

I miss MF accuracy, too. It makes you wonder why Canon does not design a screen with MF focusing aid built in along with the correct metering correction to permit their usage with any lens in any metering mode.

Wilt wrote in post #5643559
spot and partial metering can be erroneously biased by 2-3EV when the Haoda/Katz Eye are in place and the lens is slower than f/2.8

Haoda says, "Our screens have the minimal metering effect among all focusing screens!"

I know it doesn't directly apply to the current situation, buy my 2nd-generation Haoda has no noticeable effect on metering in any mode including Partial in my XT/350D, with my f/4-5.6 lens.

Almost all of the reports that I've heard of metering issues have been with Katz Eye screens with the optional brightness enhancement treatment (currently OptiBrite). Katz Eye says that slower lenses (f/4 or slower) will make the metering shift worse.

Nevertheless, the point stands: the focusing screen does affect the in-camera metering. If you rely on precise in-camera metering, replacing the focusing screen might trip you up.

Doug Pardee wrote in post #5643542
Another option is the Hong Kong-based FocusingScreen.com (select your local currency in the left column). I've never used them, and haven't heard much from anyone who has. But then, I've never heard anything bad about any supplier (including the eBay ones). Just heard a lot of good things about both Haoda and Katz Eye.

I purchased the X700 screen from them for the 350D a while back. Can't complain. It arrived promptly and included the equipment (read large pointed tweezers, etc...) to change it out. There weren't any English instructions but there are enough out there already so it wasn't much of a problem. Accuracy was bang on without need for additional shimming (original shim was still used).

At this point I have no intention to switch back to the OEM screen but I'm still testing. Focus certainly does "snap" more. The split prism on the X700 screen agrees with the focus confirmation but I generally get better precision with the surrounding matte (i.e. on the X700 screen fitted in a 350D, the split prism doesn't seem to be that much more accurate than the autofocus).

On a slower lens you do notice the surrounding matte goes darker quicker than the OEM screen with its fine matte. In bright light this isn't too much of an issue.

I'll do a proper review once I've had more time with it.

e-k