Focusing screen not square (450d/XSi)

Started May 21, 2013 | Discussions
AnthonyL
Senior MemberPosts: 1,724Gear list
Like?
Focusing screen not square (450d/XSi)
May 21, 2013

From time to time I've tried to use the focus points to try and align vertical and/or horizontal lines for instance of buildings, only to get home and find I'm having to rotate the image to get it square.

Today I belatedly tried a couple of tests using the frames of the lounge window.  In this picture the centre focus was directly on the vertical/horizontal intersection, the vertical points on the vertical bar and the horizontal points on the horizontal bar.  Handheld but that isn't the problem (I'm still fairly steady ).

A similar test using the grid lines on live view is satisfactory.

I reckon the image is about 2.15deg out.  Are there any easy solutions?

Focus points where aligned to bars when taken.

 AnthonyL's gear list:AnthonyL's gear list
Canon EOS 450D Canon EF 50mm f/1.8 II Canon EF-S 10-22mm f/3.5-4.5 USM Canon EF-S 55-250mm f/4-5.6 IS Canon EF-S 18-55mm f/3.5-5.6 IS +1 more
rsn48
Veteran MemberPosts: 7,130
Like?
When questions about image...
In reply to AnthonyL, May 21, 2013

If you are posting questions about images, the data is almost a necessity; in this case what focal length are you using.

-- hide signature --

Hindsight is better than foresight, except for lost opportunity costs.

Reply   Reply with quote   Complain
meland
Senior MemberPosts: 4,028
Like?
Re: When questions about image...
In reply to rsn48, May 21, 2013

rsn48 wrote:

If you are posting questions about images, the data is almost a necessity; in this case what focal length are you using.

What would the focal length have to do with a question such as this?

Reply   Reply with quote   Complain
TTMartin
Veteran MemberPosts: 6,667Gear list
Like?
Re: Focusing screen not square (450d/XSi)
In reply to AnthonyL, May 21, 2013

The focus screen is visible when you remove the lens.

On cameras some cameras like the 50D they are designed to be changeable.

The focus screen on the XSi it is not designed to be changable.

There is a company that makes replacement screens for the camera that has directions on how to do it.

WARNING: Focus screens are soft and scratch easily. I would not recommend messing with it.

But, if you still feel compelled to mess with it, here is a link to the directions.

http://www.katzeyeoptics.com/files/install7.pdf

 TTMartin's gear list:TTMartin's gear list
Canon PowerShot S100 (2000) Canon PowerShot SD1000 Canon EOS 40D Canon EOS 400D Canon EOS 7D +24 more
Reply   Reply with quote   Complain
AnthonyL
Senior MemberPosts: 1,724Gear list
Like?
Re: Focusing screen not square (450d/XSi)
In reply to TTMartin, May 21, 2013

TTMartin wrote:

The focus screen is visible when you remove the lens.

On cameras some cameras like the 50D they are designed to be changeable.

The focus screen on the XSi it is not designed to be changable.

There is a company that makes replacement screens for the camera that has directions on how to do it.

WARNING: Focus screens are soft and scratch easily. I would not recommend messing with it.

But, if you still feel compelled to mess with it, here is a link to the directions.

http://www.katzeyeoptics.com/files/install7.pdf

Mmm - well apart from the risk of damage I'm not convinced that I could take it out and put it back with any more accuracy so I'll take your recommendation to not mess with it.  I'll try and find a better way of ensuring that verticals are vertical and horizontals are horizontal now I know I have this problem.

 AnthonyL's gear list:AnthonyL's gear list
Canon EOS 450D Canon EF 50mm f/1.8 II Canon EF-S 10-22mm f/3.5-4.5 USM Canon EF-S 55-250mm f/4-5.6 IS Canon EF-S 18-55mm f/3.5-5.6 IS +1 more
Reply   Reply with quote   Complain
AnthonyL
Senior MemberPosts: 1,724Gear list
Like?
Re: When questions about image...
In reply to rsn48, May 21, 2013

rsn48 wrote:

If you are posting questions about images, the data is almost a necessity; in this case what focal length are you using.

I'm don't think the focal length is very relevant but if it helps you answer my question it was taken with the 18-55mm lens at 34mm at a distance of about 3m from the window.

 AnthonyL's gear list:AnthonyL's gear list
Canon EOS 450D Canon EF 50mm f/1.8 II Canon EF-S 10-22mm f/3.5-4.5 USM Canon EF-S 55-250mm f/4-5.6 IS Canon EF-S 18-55mm f/3.5-5.6 IS +1 more
Reply   Reply with quote   Complain
rsn48
Veteran MemberPosts: 7,130
Like?
If ultra wide, could be distortion
In reply to AnthonyL, May 22, 2013

I asked because if you had been shooting in the ultra wide range, disortion is the order of the day.  But you weren't shooting in that focal range.

To me it is just normal problems with hand holding.  I recognize it because I do it so much.  I shoot very fast often and as a result I get tilted images, many of them. I just fix them in post production, easy to do, take seconds.

There's nothing wrong with your camera.

-- hide signature --

Hindsight is better than foresight, except for lost opportunity costs.

Reply   Reply with quote   Complain
PhilPreston3072
Senior MemberPosts: 1,849Gear list
Like?
Re: Focusing screen not square (450d/XSi)
In reply to AnthonyL, May 22, 2013

AnthonyL wrote:

Mmm - well apart from the risk of damage I'm not convinced that I could take it out and put it back with any more accuracy so I'll take your recommendation to not mess with it.  I'll try and find a better way of ensuring that verticals are vertical and horizontals are horizontal now I know I have this problem.

If it's just the focusing screen that is out of alignment then I don't think it should cost too much for it to be serviced by technicians, since it's fairly easy to access. Hopefully no more than half the cost of a new body.

You might also want to check if your sensor is in alignment by setting your camera to manual sensor clean and visually checking if the sensor is still square with the body.

 PhilPreston3072's gear list:PhilPreston3072's gear list
Canon EOS 450D Canon EF-S 18-200mm f/3.5-5.6 IS
Reply   Reply with quote   Complain
WilbaW
Veteran MemberPosts: 8,820Gear list
Like?
Re: Focusing screen not square (450d/XSi)
In reply to AnthonyL, May 22, 2013

I'd try it on a tripod so that you can be sure it's not you tilting the camera when you press the shutter button.

It's easy to remove and replace the focus screen in a 450D if you know what you're doing, but yeah, daunting the first time and easy to mess up. 

-- hide signature --

Check out the unofficial Rebel Talk FAQ - http://snipurl.com/RebelFAQ

Reply   Reply with quote   Complain
AnthonyL
Senior MemberPosts: 1,724Gear list
Like?
Re: If ultra wide, could be distortion
In reply to rsn48, May 22, 2013

rsn48 wrote:

I asked because if you had been shooting in the ultra wide range, disortion is the order of the day.  But you weren't shooting in that focal range.

I'm not going to get that sort of extertion even with my 10-22 at 10mm.

To me it is just normal problems with hand holding.  I recognize it because I do it so much.  I shoot very fast often and as a result I get tilted images, many of them. I just fix them in post production, easy to do, take seconds.

There's nothing wrong with your camera.

I think you have not understood my issue.  The dots I see through the viewfinder line up exactly with the bars.  I have mistakenly used these to help align vertical and horizontal only to get home and find that I'm a couple of degrees out.  This is not a hand holding problem.  When I have aligned using a tripod I get the same result.  Put another way, if you look at the original image, the dots would not fit in the centre of the squares at the extremes.  If it was easy to rotate the focusing screen by 2deg then they would align.

Next time I take an image of say a building I will align the leftmost point below the horizon and the rightmost point above the horizon unless anyone has a better suggestion.

Or use the live view grid if I'm on a tripod.

 AnthonyL's gear list:AnthonyL's gear list
Canon EOS 450D Canon EF 50mm f/1.8 II Canon EF-S 10-22mm f/3.5-4.5 USM Canon EF-S 55-250mm f/4-5.6 IS Canon EF-S 18-55mm f/3.5-5.6 IS +1 more
Reply   Reply with quote   Complain
AnthonyL
Senior MemberPosts: 1,724Gear list
Like?
Re: Focusing screen not square (450d/XSi)
In reply to WilbaW, May 22, 2013

WilbaW wrote:

I'd try it on a tripod so that you can be sure it's not you tilting the camera when you press the shutter button.

Tripod makes no difference.  The dots don't align exactly with the squares.

It's easy to remove and replace the focus screen in a 450D if you know what you're doing, but yeah, daunting the first time and easy to mess up. 

I don't know if replacing would make a difference, I was hoping to rotate.

-- hide signature --

Check out the unofficial Rebel Talk FAQ - http://snipurl.com/RebelFAQ

Do you have the full URL for the RebelFAQ site - Firefox is warning me against going to that URL, presumably because snipurl has been used for linking to some dodgy sites?

 AnthonyL's gear list:AnthonyL's gear list
Canon EOS 450D Canon EF 50mm f/1.8 II Canon EF-S 10-22mm f/3.5-4.5 USM Canon EF-S 55-250mm f/4-5.6 IS Canon EF-S 18-55mm f/3.5-5.6 IS +1 more
Reply   Reply with quote   Complain
meland
Senior MemberPosts: 4,028
Like?
Re: Focusing screen not square (450d/XSi)
In reply to AnthonyL, May 22, 2013

AnthonyL wrote:

WilbaW wrote:

I'd try it on a tripod so that you can be sure it's not you tilting the camera when you press the shutter button.

Tripod makes no difference.  The dots don't align exactly with the squares.

It's easy to remove and replace the focus screen in a 450D if you know what you're doing, but yeah, daunting the first time and easy to mess up. 

I don't know if replacing would make a difference, I was hoping to rotate.

-- hide signature --

Check out the unofficial Rebel Talk FAQ - http://snipurl.com/RebelFAQ

Do you have the full URL for the RebelFAQ site - Firefox is warning me against going to that URL, presumably because snipurl has been used for linking to some dodgy sites?

If you do a google search on "Focusing screen in Canon not aligned" or similar you will see that this is a fairly common issue, especially on the Rebel / xxx class models and I'm not sure there is much that can be done about correcting it I'm afraid.

You could use the frame of the focussing screen for lining up horizontals perhaps rather than relying on the AF points, as this should be aligned correctly even if the focussing screen with its etched AF points are slightly out.

Reply   Reply with quote   Complain
Y0GI
Veteran MemberPosts: 5,210Gear list
Like?
Re: Focusing screen not square (450d/XSi)
In reply to AnthonyL, May 22, 2013

AnthonyL wrote:

WilbaW wrote:

I'd try it on a tripod so that you can be sure it's not you tilting the camera when you press the shutter button.

Tripod makes no difference.  The dots don't align exactly with the squares.

It's easy to remove and replace the focus screen in a 450D if you know what you're doing, but yeah, daunting the first time and easy to mess up. 

I don't know if replacing would make a difference, I was hoping to rotate.

-- hide signature --

Check out the unofficial Rebel Talk FAQ - http://snipurl.com/RebelFAQ

Do you have the full URL for the RebelFAQ site - Firefox is warning me against going to that URL, presumably because snipurl has been used for linking to some dodgy sites?

Here is a direct link to the FAQs.

And Here is a focus screen tutorial for the XSi/450D.

Good luck!

-- hide signature --

Yogi
When you get down to the nuts and bolts of photography, the results depend on the 'nut' behind the camera!
See the 'Gear List' in my 'Profile' for my current equipment.
Check out WilbaW's beginner FAQs at - http://snipurl.com/RebelFAQ

 Y0GI's gear list:Y0GI's gear list
Canon EOS 7D Canon EF-S 10-22mm f/3.5-4.5 USM Canon EF-S 17-55mm f/2.8 IS USM Canon EF 100-400mm f/4.5-5.6L IS USM +2 more
Reply   Reply with quote   Complain
photonius
Veteran MemberPosts: 6,138
Like?
Re: If ultra wide, could be distortion
In reply to rsn48, May 22, 2013

rsn48 wrote:

I asked because if you had been shooting in the ultra wide range, disortion is the order of the day.  But you weren't shooting in that focal range.

To me it is just normal problems with hand holding.  I recognize it because I do it so much.  I shoot very fast often and as a result I get tilted images, many of them. I just fix them in post production, easy to do, take seconds.

There's nothing wrong with your camera.

I wouldn't bet on it.

-- hide signature --

Hindsight is better than foresight, except for lost opportunity costs.

-- hide signature --

*** Life is short, time to zoom in *** ©

Reply   Reply with quote   Complain
photonius
Veteran MemberPosts: 6,138
Like?
Re: Focusing screen not square (450d/XSi)
In reply to AnthonyL, May 22, 2013

AnthonyL wrote:

WilbaW wrote:

I'd try it on a tripod so that you can be sure it's not you tilting the camera when you press the shutter button.

Tripod makes no difference.  The dots don't align exactly with the squares.

It's easy to remove and replace the focus screen in a 450D if you know what you're doing, but yeah, daunting the first time and easy to mess up. 

I don't know if replacing would make a difference, I was hoping to rotate.

I have the same feeling with my 550D, I tried  using the dots for alignment, and then it's not straight in the final picture. I have not done a rigorous test, but when I tilt the camera a bit so the dots don't quite line up (in opposite direction of the tilt), then it looks more straight afterwards. As suggested, in live view that problem shouldn't exist.

I suspect it may not be unusually for the viewfinder to be off by 1 or 2 degrees - which is of course not desired. I will have to test it seriously with the camera on a tripod and a level to make sure all is perfectly aligned (a horizon may not always be horizontal either).

The reason I am not surprised about variation is that in my 550D, the central spot exposure metering point was actually not in the center at all, but substantially off to the right. Took Canon several attempts to fix it, because initially they didn't figure out what was wrong, I had to pinpoint the exposure problem for them.

-- hide signature --

Check out the unofficial Rebel Talk FAQ - http://snipurl.com/RebelFAQ

Do you have the full URL for the RebelFAQ site - Firefox is warning me against going to that URL, presumably because snipurl has been used for linking to some dodgy sites?

-- hide signature --

*** Life is short, time to zoom in *** ©

Reply   Reply with quote   Complain
WilbaW
Veteran MemberPosts: 8,820Gear list
Like?
Re: Focusing screen not square (450d/XSi)
In reply to AnthonyL, May 22, 2013

AnthonyL wrote:

WilbaW wrote:

It's easy to remove and replace the focus screen in a 450D if you know what you're doing, but yeah, daunting the first time and easy to mess up. 

I don't know if replacing would make a difference, I was hoping to rotate.

Just in case we're misunderstanding each other, when I said replace I meant put it back in again to see if seated better, I didn't mean put in a replacement.

Check out the unofficial Rebel Talk FAQ - http://snipurl.com/RebelFAQ

Do you have the full URL for the RebelFAQ site - Firefox is warning me against going to that URL, presumably because snipurl has been used for linking to some dodgy sites?

Ow, first time I've seen that. Thanks for letting me know. I can't tell whether it's a problem with snipurl itself or some sites you get to via its redirection. I'd better use the direct link in my sig for a while.

-- hide signature --

Check out the unofficial Rebel Talk FAQ - http://www.dpreview.com/articles/1905744226/rebel-forum-faq

Reply   Reply with quote   Complain
Midwest
Forum ProPosts: 14,194
Like?
Re: Focusing screen not square (450d/XSi)
In reply to WilbaW, May 22, 2013

WilbaW wrote:

AnthonyL wrote:

WilbaW wrote:

It's easy to remove and replace the focus screen in a 450D if you know what you're doing, but yeah, daunting the first time and easy to mess up. 

I don't know if replacing would make a difference, I was hoping to rotate.

Just in case we're misunderstanding each other, when I said replace I meant put it back in again to see if seated better, I didn't mean put in a replacement.

Check out the unofficial Rebel Talk FAQ - http://snipurl.com/RebelFAQ

Do you have the full URL for the RebelFAQ site - Firefox is warning me against going to that URL, presumably because snipurl has been used for linking to some dodgy sites?

Ow, first time I've seen that. Thanks for letting me know. I can't tell whether it's a problem with snipurl itself or some sites you get to via its redirection. I'd better use the direct link in my sig for a while.

I've gotten that sort of warning before on links that used something called tiny url - I guess because it disguises the true address of where you're heading when you click the link.

Reply   Reply with quote   Complain
mfait
Contributing MemberPosts: 576Gear list
Like?
Re: Focusing screen not square (450d/XSi)
In reply to AnthonyL, May 22, 2013

AnthonyL wrote:

From time to time I've tried to use the focus points to try and align vertical and/or horizontal lines for instance of buildings, only to get home and find I'm having to rotate the image to get it square.

Today I belatedly tried a couple of tests using the frames of the lounge window.  In this picture the centre focus was directly on the vertical/horizontal intersection, the vertical points on the vertical bar and the horizontal points on the horizontal bar.  Handheld but that isn't the problem (I'm still fairly steady ).

A similar test using the grid lines on live view is satisfactory.

I reckon the image is about 2.15deg out.  Are there any easy solutions?

You don't actually see through the focusing screen.  The focusing screen is under the mirror.  The focus points are for display purposes in the viewfinder so you know where they are located.

See http://www.dyxum.com/columns/photoworld/fundamentals/optical_viewfinder.asp

Therefore, either you mirror or your pentamirror is a bit off tilting the image in the viewfinder.

 mfait's gear list:mfait's gear list
Canon PowerShot S100 Canon EOS 450D
Reply   Reply with quote   Complain
TTMartin
Veteran MemberPosts: 6,667Gear list
Like?
Re: Focusing screen not square (450d/XSi)
In reply to mfait, May 22, 2013

mfait wrote:

AnthonyL wrote:

From time to time I've tried to use the focus points to try and align vertical and/or horizontal lines for instance of buildings, only to get home and find I'm having to rotate the image to get it square.

Today I belatedly tried a couple of tests using the frames of the lounge window.  In this picture the centre focus was directly on the vertical/horizontal intersection, the vertical points on the vertical bar and the horizontal points on the horizontal bar.  Handheld but that isn't the problem (I'm still fairly steady ).

A similar test using the grid lines on live view is satisfactory.

I reckon the image is about 2.15deg out.  Are there any easy solutions?

You don't actually see through the focusing screen.  The focusing screen is under the mirror.  The focus points are for display purposes in the viewfinder so you know where they are located.

See http://www.dyxum.com/columns/photoworld/fundamentals/optical_viewfinder.asp

Therefore, either you mirror or your pentamirror is a bit off tilting the image in the viewfinder.

You don't see through the focusing screen, but, you do see the image projected ON the focusing screen.

On the 450d/XSi focus squares are etched on the focus screen.

Tilting a mirror does not rotate the image.

 TTMartin's gear list:TTMartin's gear list
Canon PowerShot S100 (2000) Canon PowerShot SD1000 Canon EOS 40D Canon EOS 400D Canon EOS 7D +24 more
Reply   Reply with quote   Complain
mfait
Contributing MemberPosts: 576Gear list
Like?
Re: Focusing screen not square (450d/XSi)
In reply to TTMartin, May 22, 2013

TTMartin wrote:

mfait wrote:

AnthonyL wrote:

From time to time I've tried to use the focus points to try and align vertical and/or horizontal lines for instance of buildings, only to get home and find I'm having to rotate the image to get it square.

Today I belatedly tried a couple of tests using the frames of the lounge window.  In this picture the centre focus was directly on the vertical/horizontal intersection, the vertical points on the vertical bar and the horizontal points on the horizontal bar.  Handheld but that isn't the problem (I'm still fairly steady ).

A similar test using the grid lines on live view is satisfactory.

I reckon the image is about 2.15deg out.  Are there any easy solutions?

You don't actually see through the focusing screen.  The focusing screen is under the mirror.  The focus points are for display purposes in the viewfinder so you know where they are located.

See http://www.dyxum.com/columns/photoworld/fundamentals/optical_viewfinder.asp

Therefore, either you mirror or your pentamirror is a bit off tilting the image in the viewfinder.

You don't see through the focusing screen, but, you do see the image projected ON the focusing screen.

On the 450d/XSi focus squares are etched on the focus screen.

Tilting a mirror does not rotate the image.

Thanks for the correction.  I was thinking about the focus sensor.

 mfait's gear list:mfait's gear list
Canon PowerShot S100 Canon EOS 450D
Reply   Reply with quote   Complain
Keyboard shortcuts:
FForum MMy threads