Mucky focussing screen - do I care?

[CommanderJameson]

I've got specks of dust on the focussing screen of my 550D. Does this compromise the camera's ability to focus?

Will dropping £20 on a new one make any difference?

[markmullen]

No and No.

A gridded focussing screen will help ensure your horizons don't end up on the piss if you want to replace it.

[CommanderJameson]

Excellent, cheers.

Gridded focus screen might be a plan. Horizons on the piss is a common problem amongst photographers my age.

[Simpo Two]

There may be a grid option in the custom menu - have a look there first.

[markmullen]

Simpo Two said:

There may be a grid option in the custom menu - have a look there first.

There is for liveview but not for viewfinder.

[gingerpaul]

I've just changed the one in my 5D2 for the Canon "Super Precision Matte Focusing Screen" to help me manual focus some of my fast primes and I've been really impressed just in case you might be interested in that.

It gives much better differentiation between in and out of focus areas making it easier to manual focus accurately. It darkens the viewfinder with lenses slower that f/2.8 though just as a warning, although the 24-105 and 17-40 are still perfectly usable if necessary.

[Craikeybaby]

Have you tried cleaning it with a rocket blower etc?

[Kermit power]

gingerpaul said:

I've just changed the one in my 5D2 for the Canon "Super Precision Matte Focusing Screen" to help me manual focus some of my fast primes and I've been really impressed just in case you might be interested in that.

It gives much better differentiation between in and out of focus areas making it easier to manual focus accurately. It darkens the viewfinder with lenses slower that f/2.8 though just as a warning, although the 24-105 and 17-40 are still perfectly usable if necessary.

Are you sure it's darkening the screen with lenses slower than f2.8? I would assume it's actually lightening up the screen for lenses faster than f4 or so?

[Kermit power]

I wish I could easily swap out the focusing screen in my 7D. I'd love an old style split prism screen for manual focusing, but only if I could easily swap back to using the standard screen for AF on moving objects.

[CommanderJameson]

Kermit power said:

I wish I could easily swap out the focusing screen in my 7D. I'd love an old style split prism screen for manual focusing, but only if I could easily swap back to using the standard screen for AF on moving objects.

You can.

http://www.focusingscreen.com/work/7den.htm

Depends on your definition of "easy", of course.

[gingerpaul]

Kermit power said:

Are you sure it's darkening the screen with lenses slower than f2.8? I would assume it's actually lightening up the screen for lenses faster than f4 or so?

Yep, definitely darker. I don't understand the physics of what's going on inside I'm afraid so I can't explain why. I'm curious now so will look it up later!

[Kermit power]

CommanderJameson said:

Kermit power said:

I wish I could easily swap out the focusing screen in my 7D. I'd love an old style split prism screen for manual focusing, but only if I could easily swap back to using the standard screen for AF on moving objects.

You can.

http://www.focusingscreen.com/work/7den.htm

Depends on your definition of "easy", of course.

I was thinking more being able to swap it in the way you'd swap a lens - take care not to get dust in, but otherwise something you can do on the fly when you're out and about.

However, I'd always previously understood that you'd lose the AF point indicators if you changed the focusing screen, but those instructions suggest this isn't the case???

Must now seek confirmation!

[tog]

gingerpaul said:

Kermit power said:

Are you sure it's darkening the screen with lenses slower than f2.8? I would assume it's actually lightening up the screen for lenses faster than f4 or so?

Yep, definitely darker. I don't understand the physics of what's going on inside I'm afraid so I can't explain why. I'm curious now so will look it up later!

I had one of my 5D2s fitted with this screen, and found even my 2.8 lenses very dark, I'd not have wanted to use F4 lenses with it. Lovely with fast primes though. Shame the 5D3 can't be changed (within my definition of easily!).

[gingerpaul]

tog said:

I had one of my 5D2s fitted with this screen, and found even my 2.8 lenses very dark, I'd not have wanted to use F4 lenses with it. Lovely with fast primes though. Shame the 5D3 can't be changed (within my definition of easily!).

What's the procedure with the 5D3 then? I couldn't believe how easy it was on the 5D2. Easy enough that if I was shooting in the dark with a slow zoom and only had one body with me it's easy enough to change back. I'm amazed Canon don't make more of a noise about it.

[tog]

I haven't looked into it to be honest, but according to Canon it is not interchangeable. It has the fancy pants LCD panel focusing points built into it (is that like the 7D?).

[RobDickinson]

CommanderJameson said:

I've got specks of dust on the focussing screen of my 550D. Does this compromise the camera's ability to focus?

The focus module is way down in the base of the mount entrance under the mirror and in front of the shutter. Focus screens dont affect autofocus. THe metering system though is up in the same assembly and is calibrated with the current focus screen, without a custom function to tell it you have fitted a different one (not available on many canons :/) the metering will be off, often by a non linear amount.

Also focus screens are very delicate and easy to scratch so if you do more than rocket blower them be very very careful.

[gingerpaul]

tog said:

I haven't looked into it to be honest, but according to Canon it is not interchangeable. It has the fancy pants LCD panel focusing points built into it (is that like the 7D?).

That's a shame. I've only used a 5D3 in passing but was very impressed with the autofocusing system. It's still nice to check the eyes are in focus in a portrait though.

[tog]

gingerpaul said:

tog said:

I haven't looked into it to be honest, but according to Canon it is not interchangeable. It has the fancy pants LCD panel focusing points built into it (is that like the 7D?).

That's a shame. I've only used a 5D3 in passing but was very impressed with the autofocusing system. It's still nice to check the eyes are in focus in a portrait though.

Focussing with the 5D3 is streets ahead of the 5D2, but the screen is not as nice, and in certain lights you get a red flare across most of the screen as it lights up the selected focus point.

[ian in lancs]

CommanderJameson said:

Kermit power said:

I wish I could easily swap out the focusing screen in my 7D. I'd love an old style split prism screen for manual focusing, but only if I could easily swap back to using the standard screen for AF on moving objects.

You can.

http://www.focusingscreen.com/work/7den.htm

Depends on your definition of "easy", of course.

That's a bit off a faff! They clip in on a Nikon d300, d700 and d3 and I change them to suit what I'm doing.

Edited by ian in lancs on Sunday 28th April 21:51

[Kermit power]

CommanderJameson said:

Kermit power said:

I wish I could easily swap out the focusing screen in my 7D. I'd love an old style split prism screen for manual focusing, but only if I could easily swap back to using the standard screen for AF on moving objects.

You can.

http://www.focusingscreen.com/work/7den.htm

Depends on your definition of "easy", of course.

I'm still not really clear on this. Is there actually any downside to fitting this screen to my 7D?