Viewfinder VS captured image. Help please

[I X L R 8]

I have , for a long time , been under the impression that SLR cameras capture the exact image seen in the viewfinder.

I'm finding for some reason that this is not the case with digital.

Also, I'm not so sure it was the case with my Minolta 700si 35mm film camera.

On the Sony A550, the processed image, is larger than the image seen in the viewfinder before the shot.

In other words, if I put the edge of the frame in the viewfinder, on a lateral line and then snap the shot, the processed image overlaps the line.

This is hard to explain.

I'm wondering if there is a setting that allows to capture the exact image seen in the viewfinder?????

I've noted that when I change aspect ratios and megapixels, this does change some but it is still not the exact image seen in the viewfinder.

Anyone?

 

[I X L R 8]

bump

 

[Brutus]

I believe there is normally a magnification factor in most viewfinders.

 

[AdrianC]

That's just how the camera was designed. I remember reading about it in my user manual a couple of yrs ago.

You could just crop it during post processing.

 

[Bitter Jeweler]

You really want to over shoot anyways. This gives you room to refine the crop later. So, look at it as a positive.

 

[I X L R 8]

Thank you.
I found the problem.

16:9 aspect ratio changes the image capture seen in the viewfinder.

I changed that back to 3:2 aspect ratio which is the equivalent of a 35mm.
The camera became MUCH MORE viewfinder to processed image friendly.

Obviously I don't know what I'm doing.
But alas , all is not lost.
I'm trying to figure it all out.

 

[Dwig]

I have , for a long time , been under the impression that SLR cameras capture the exact image seen in the viewfinder...

You have been living with a false impression. Almost none ever have.

With a few exceptions, neither film nor digital SLRs have extremely accurate VFs. In almost all cases the VF image is 5-10% smaller area than the actual film or sensor. Making an SLR VF perfectly accurate is extremely difficult (read: expensive).

 

[Scatterbrained]

I have , for a long time , been under the impression that SLR cameras capture the exact image seen in the viewfinder...

You have been living with a false impression. Almost none ever have.

With a few exceptions, neither film nor digital SLRs have extremely accurate VFs. In almost all cases the VF image is 5-10% smaller area than the actual film or sensor. Making an SLR VF perfectly accurate is extremely difficult (read: expensive).

+1. If you look most cameras will have a specification for viewfinder coverage area. I think mine is about 95%, which means that 5% of what will be captured by my camera cannot be seen through the viewfinder. I've just adjusted to cropping that extra out of my images.

 

[Dao]

I do not think it is going to be exactly the same, but in general, those camera bodies that cost more have more coverage.

My Canon 40D claims to be 95% frame coverage while 1Ds MKIII is 100%.

And your A550 also claims to be 95% frame coverage.

 

[KmH]

When you look in the viewfinder the lens is kept wide open so the viewfinder is a bright as possible.

When the shutter is released, or a DOF preview button is pressed, THEN the lens aperture is physically set by the camera.

At any rate the light path to get the scene up to the eye is different than the light path to the image sensor.
Additionally, the image sensor doesn't work like your eye does.

Cross-section view of DSLR system:

1. 4-element lens
2. Reflex mirror
3. Focal-plane shutter
4. Image sensor
5. Matte focusing screen
6. Condenser lens
7. Pentaprism or Pentamirror
8. Eyepiece

I, Cburnett, the copyright holder of this work, hereby publish it under the following licenses:
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

 

[Taylor510ce]

Canon 7D has 100%

 

[I X L R 8]

thank you all for being so helpful.

The 3.2 aspect ratio cured the problem I was having.
With this ratio, a bit more is captured " evenly on all sides" than what I see in the viewfinder.

The 16:9 ratio distorts the processed image. Dont ask me why.
I'M QUITE OBVIOUSLY A ROOKIE.