Finally a cure for Canon AF

Just got a split/matte focus screen from Haoda Fu installed and working on my 20D. What a treat! So far I've only been shooting samples, but the results are impressive.

Here's a test shot I took with the Sigma 20mm at f/1.8 (Parameter 1):



Auto-focused (on the left eye):



Manually focused:



I have shot after shot demonstrating this. Unless you're careless, it's pretty hard not to meet or exceed the accuracy of Canon's AF with this screen.

n/t

Can you tell me more about this screen?
How it works, where to get one?

Thanks

Jaymzz said:

Just got a split/matte focus screen from Haoda Fu installed and
working on my 20D. What a treat! So far I've only been shooting
samples, but the results are impressive.

Here's a test shot I took with the Sigma 20mm at f/1.8 (Parameter 1):



Auto-focused (on the left eye):



Manually focused:



I have shot after shot demonstrating this. Unless you're careless,
it's pretty hard not to meet or exceed the accuracy of Canon's AF
with this screen.

Click to expand...

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• Jared -

I cannot make out what your text and test images are saying. You have installed an aftermarket screen that I understand so far. Which image are you illustrating benefit of the new screen-the Auto Focused or the Manual one? I am an events shooter and like many, I have had inconsistent focusing issues with my 20D and a number of L lenses that I use. The speed and accuracy of AF focusing is critical for me.

Is the aftermarket screen effective for fast Auto Focus? I have read about its usefulness for Manual Focus.

--
Jan Shim (CPS)
Professional Events Photography
http://www.janshim.com

For your info, I found this link with all the info and with instruction in PDF.
Regards,
Daniel

Here the link :
http://groups.yahoo.com/group/screen4DSLR/

I'm assuming that installing this after-market item will void the manufacturer's warranty. Is it really worth the risk?

I'm trying to say that I can focus more accurately with Haoda's screen than the autofocus system can. This has been an issue since I stated shooting autofocus cameras in the late 1990s... while I appreciated not having to focus myself, I always thought I was giving up some accuracy in doing it.

This image is pretty typical of my Sigma 20mm, which has great optics but sometimes iffy results in the field. On the other hand, AF seems pretty good on the Canon 85mm f/1.8 which is rarely off my much.

I found that manual focus was more accurate for focusing than auto focus, but auto focus is faster than I am. Maybe I'll get faster, but I don't know think I'll ever be as fast as an AF system. When I shot with a manual focus camera, I used to try to anticipate shots at events (focus on 15' when someone was 20' away and getting closer) and I don't think I did any worse than the 20D does at it. I've found that if I want consistent AF results on the 20D I have to half-press 2-3x and that wipes out the speed advantage.

I imagine my use for this screen - when not taking test shots - will be to be able to visually confirm the focus when auto focusing. I don't know if you'd have time to do that shooting events. As a hobbyist, nothing about this is critical for me, so $75 is more or less a cheap thrill. I was just surprised at how well it works.

Given that Canon sells alternate screens for the 20D, I doubt it could void the warranty. That would be like Canon voiding the warranty if you changed the batteries or CF card. If you put the battery in incorrectly and damaged the camera, that might be another story. This is a pretty easy change, the most risk is to the new screen itself.

Elias K said:

I'm assuming that installing this after-market item will void the
manufacturer's warranty. Is it really worth the risk?

Click to expand...

Do the autofocus points still show up on the viewing screen? They seem to be marked on the Canon supplied screen.

--
http://www.pbase.com/ejohnw/
http://www.ejohnphoto.com/
eJohn Waldron

To my knowledge alternate screens are only sold for the 1 series, not xx or xxx, so its likely to void the warranty - but thats an interesting point and should be cleared up

Depends on the camera - afaik 300D wont show AF Points any more, but 20D does.

OK, so the Hoada or equivalent focusing screens are an aid to better (Manual) focus and it doesn't help the camera improve it's AF at all. I have lately trained my eye to look for possible back focusing and am happy to report that it is possible.

I recently shot a signing ceremony on the 20D and 24-70mm. Had an AF point locked on the person only to notice that the camera had focused on the wall behind him. With shutter still half-depressed, I turned the manual focusing ring to bring the person in focus then nail the shot.

It's not an easy thing to spot though but when I can, I overcome what would turn out to be an back focused shot. Every keeper counts.

--
Jan Shim (CPS)
Professional Events Photography
http://www.janshim.com

You need to re-calibrate your lens or to rechip it.

I had the same problem with my 100-400L IS and calibration helped.
For example, this shot 400mm at f5.6:

The results in this example are not coincidental, I did few tests and the results were consistent before and after calibration.



--
Elroyie

http://www.pbase.com/elroyie

You need to check first if your camera is calibrated.
--
Elroyie

http://www.pbase.com/elroyie

The AF is usually within the specified 1/3 of a DOF as the 20D is spec'd for my faster lenses. The problem is two-fold:

1. The AF system may choose something else within it's range to focus on than I wanted it to.

2. Me with the screen seems to be able to meet or exceed 1/3 DOF most of the time.

Take this shot, which is at f/1.8 on a 20mm lens at 2 feet.

http://www.dofmaster.com/dofjs.html

I get a DOF of 0.2 feet = 2.4". The 20D should focus on the eye within 1/3 of that or about 0.8". So it did miss the eye, but the stripes behind the eye which ARE in focus are about 0.5" away from my focus point. If I took this camera in to be calibrated by Canon I think they would laugh at me. If I want to do better, I'm stuck with the built-in matte screen or Haoda's.

... in most states of the U. S., you can do whatever you want to a product that you own, without voiding the warranty.

In Ohio, as long as your modification (you've painted your D20 white, for example) doesn't cause the failure ("I can't see the LCD any more!") then it's covered.

If you mod causes or adds to the problem, then you eat it. Also, if you take something apart something with a 'workmanship' warranty, that part is no longer valid, as the 'workmanship' is no longer under their control.
Your state's consumer product website will have the details.
Ken

--



http://www.ahomls.com/gallery.htm
Voted Best of the City 2004 by Cincinnati Magazine
I don't believe in fate, but I do believe in f/8!

You could focus on the eyebrow. :^)

I have the haoda screen, but don't have any wide angle lenses, all my telephoto primes, and 50 1.4 if you don't consider that telephoto, focus perfect. I only wish the screen worked better with my 400 f5.6L, but none of them work well with f5.6 lenses.

the only time the screen really helps is when my subject is small in the frame and far away, otherwise the autofocus does just as good a job as me.
--



Narrow depth of field ahead
Use extreme caution

http://www.pbase.com/paulyoly/root