20D - improved Katz Eye focsuing screen - Part 1/1

Started Aug 13, 2005 | Discussions thread
HMetal Contributing Member • Posts: 990
Or not.. Comments on BOTH screens

DigitalWolf wrote:

That's quite the assumption you make. There's a lot of information to take in with these screens and I don't believe Doug has tried Haoda's screen, first-hand.

I wasn't even going to mention this at this point, as I wanted to do more testing to make my report 100% fair but..

I finally have BOTH Haoda's original screen (not his new model) and Katz Eye's new "Plus" screen.

I have tested both screens under similar circumstances. I've done portrait, wildlife and macro photography with them and have the following comments and observations:

First of all, the Katz Eye screen is superior as far as a focusing aid goes. It is easier to focus manually than Haoda's. The fluid or organic prism effect is more noticable and you can attain manual focus a lot easier. With Haoda's screen, you have to pay a little more attention to the prism. It is easier to see with Rachael's when focus is attained.

With both screens, there was no discernable difference or difficulty in focusing using the split image.

So, if focusing alone were the determining factor, I would go with the Katz Eye lens hands down. This might change if I can get a hold of one of Haoda's newer screen, though I've paid my bit. I won't be buying another screen for my 20D. Screen donations for further testing are welcomed.

However, focusing is not the only factor you need to be concerned about with these screens. There is a metering effect to be concerned about.

Haoda's screen has no discernable effect on metering for all apertures and shutter speeds that I have shot. Which means, I can set my 20D on Av mode and shoot just as I could with the stock Canon screen.

Conversely, the Katz Eye screen works excellent and metering isn't off much (maybe +1/3 stop) with faster lenses (tested with F1.8 and F2.8 lenses). Unfortunately, there is a down side with the Katz Eye screen and for those who use (slower) super telephoto lenses, it may be the determining factor.

The singular problem with the Katz Eye screen is that with slower lenses (e.g. the Canon 100-400mm F4.5-5.6 IS), the metering is affected in such a way that most images I've shot were overexposed by as much as +2ev at F/5.6 and up, which means I had to correct by applying exposure compensation of -2ev before shooting. This is a huge problem if you shoot wildlife or action/reportage photography. In cases like this, you can't always test beforehand. You may get only one chance in a lifetime for a given shot.

So, my observations are that if you only use faster lenses of F2.8 and better, or if you can handle (have the time to, in a live situation) having to test aperatures to figure out how much exposure compensation you'll need to apply before taking the real shot, go with the Katz Eye screen.

If you use slower lenses and expect Av mode to get your exposure spot-on, I wouldn't recommend the Katz Eye screen.

Just so everyone knows, I have spoken (in email) with Rachael on this issue and she's aware of it. Doug Kerr even made an excellent technical post on this, and the reason for it, in his review. Apparently, there is a way to get around this issue with Rachael's screen using centerweighted average metering (and possibly partial metering). I haven't tried it but Rachael told me that this will get the exposure closer to what you would get with the stock screen and Haoda's screen. If and when I get a change to retest this with Rachael's screen, I'll let you know.

Oh, before anyone asks, I'm using Haoda's screen 24/7 now as it fits my needs the best. I do a lot of wildlife photography with the Canon 100-400mm.

Note: I have not tried either screen in the studio with flash lighting as of yet. There may be a whole other set of issues there of which we aren't yet aware.. I'll let you all know once I do.

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Ray A. Akey
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