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Old 22-12-2008, 05:48 PM
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40D focus question

I've been getting plenty of practice using my new 40D and so far it's been mostly positive.

But I've noticed something odd which I hope someone here might be able to explain.

I spend a lot of time getting the focus right in Live View of my terrestrial subject, zoomed in to 5 or 10x to really get a close-up view on the rear LCD screen during focusing. I use AF before tweeking the focus manually.

I take the shot...and then preview it on the LCD screen. However, when I zoom in to 5 or 10x I find the image on the LCD screen is soft and nothing like the sharp image I had prior to taking the shot.

I'm using a fast enough shutter speed. My ISO is normally 400...or thereabouts. I try and keep the aperture at a reasonable position for depth of field. I've tried with AF both on and off on the lens.

I'm shooting in RAW+JPEG (small).

Every time the same result.

Is this due to the resolution of the rear LCD monitor or what???

I'll keep Googling and searching the net to try and find an answer, but I thought I'd also put the question out there among the IIS Canon devotees.

Thanks
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Old 22-12-2008, 06:16 PM
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RB (Andrew)
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Are the images sharp and in focus when you view them on the computer screen?
Don't forget the LCD screen is only low res and the camera has to downsize the image to display it on the LCD.
As long as the images are fine on your computer then it's working ok.
The LCD is only really used to do quick checks on composition, exposure (via histogram) and basically see if your happy with the shot.

Post some examples Matt so we can have a look.
Usually when using AF, if you've got the right aperture and have set the focus points well, AF nails it every time.

The only possibility is if your lens if back/front focusing, but it doesn't sound like it.
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Old 22-12-2008, 06:21 PM
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Hi Andrew.

Thanks for the reply

Images look OK on the computer screen. I do a little sharpening...but that's normal. I'd assume you sharpen in processing to some extent?

I won't post examples...as the question was more about the LCD preview screen and clarity of preview images Vs playback, unless I've missed your point?

It just seemed odd that the image was in sharp focus in preview...and then blurred in playback...using the same factor of zoom

Thanks for your help anyway, mate
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Old 22-12-2008, 06:30 PM
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RB (Andrew)
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My livefocus is a little different on the 20Da so I can't check, but I'd say it's just normal for the new models to show this behaviour.
As long as you're happy with the images on the computer.

It's recommended that a little sharpening be applied to all images, especially with RAW files.
Canon cameras do have a slightly softer image generally due to the algorithms that Canon uses I believe.

As you probably know you can also set sharpness levels in the Custom Functions too, but I always check it in Photoshop later.
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Old 22-12-2008, 06:37 PM
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Yeah...I've been looking at setting sharpness in Custom functions.

I'm just finding it hard to get my head around why the image looks sharp at even 10x magnification in Live View...when I'm manually focusing...only to see it 'soft' in playback.

So, what's different about the Live View image, compared to the captured image viewed in playback?

How is the camera creating an image in Live View?

Perhaps some of the quality is sacrificed to speed up the playback process?
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Old 22-12-2008, 07:40 PM
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Hi Matt,

I think you've answered your question in your last post. I reckon that some quality is sacrificed as well to speed up the playback and scrolling through pics on the LCD screen. I noticed the same thing focusing on a distant terrestrial landmark with my 40D. Once viewed on the computer screen they look fine though!

Troy
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Old 22-12-2008, 07:51 PM
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Hey Troy.

Yes. Giving this more thought it seems logical.

This is even further supported by the fact there's an option in one of the menus for shooting without the CF card.

I assume this means images are stored temporarily in an on-board buffer/cache - the same place where preview images are stored/generated. I'm guessing this is not at the same resolution as what would be stored on the CF card as a RAW or large JPEG.

So, the upshot of this is, the image we see in preview on the LCD screen after we take a shot is not the same quality of data which gets sent to a CF card when it's being used.

Coupled with this is the fact the LCD preview screen is, as RB has pointed out, not hi res.

It's starting to make sense to me.
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Old 22-12-2008, 07:51 PM
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Matt, I don’t do any in-camera sharpening, I simply shoot RAW.

When shooting RAW, the only parameters set in concrete when you press the shutter release are the shutter speed, lens aperture and film speed (ISO). So, when you transfer the RAW files to your PC for processing, you can optimally adjust other parameters such as white balance, saturation, levels, curves, sharpening, noise, on the full RAW data to get the result you want.

When shooting JPGs, the camera “bakes” in the “recipe” in-camera and this leaves you less “processing space” and flexibility when using image processing applications such as Photoshop.

RAW is like leaving the recipe ingredients un-baked, so you can then adjust the quantities in PS and bake several “different” cakes from the one RAW file to suit your taste.

Having said all of that, if you’re just taking happy snaps on a day’s outing, it might be worth just shooting JPG’s as you will not have the processing and conversion overheads at the computer.

Cheers

Dennis
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Old 22-12-2008, 07:53 PM
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Quote:
Originally Posted by matt View Post
Yeah...I've been looking at setting sharpness in Custom functions.

I'm just finding it hard to get my head around why the image looks sharp at even 10x magnification in Live View...when I'm manually focusing...only to see it 'soft' in playback.
>snip
IIRC the 40D does do some sharpening when zoomed in using Live View to help with getting that sweet spot.

Cheers

Dennis
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Old 22-12-2008, 08:03 PM
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True, Dennis.

I've set my 40D to do this. It's something you have to enable in the custom functions.

Once you've let the camera do this you can manually tweek the focus ring if the focus is still just a little off.
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Old 22-12-2008, 08:46 PM
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I don't know if I'm stating the obvious here...but here goes!

For astro stuff, I autofocus, check/tweak in LiveView, when happy with focus I switch lens AF switch back to manual focus. I have found that if I leave AF on, the lens will search for focus when shutter is pressed (via laptop).
Doug
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Old 22-12-2008, 08:47 PM
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Appreciate the input, Doug.

What might be 'obvious' to one may not be the same to others, particularly to those just starting out or early in their journey.

Cheers
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Old 24-12-2008, 06:49 PM
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Hi again Matt,

Quick story for you... at work today a coworker brought in his brand new 40D. Had a quick look and it looked just the same as mine as you'd expect. However his firmware was showing as 1.1.0 whereas mine is at 1.08. I quickly raced back to my desk and jumped on the Canon site to see what the new firmware was about only to find no 1.1.0 firmware available. So after a bit of googling around I found that the 1.1.0 firmware is not yet available to the public but is available at the Canon service centers.

I managed to track down a copy of the 1.1.0 firmware (not sure if I'm allowed to link to it here) and load it up on my 40D. First (and only) thing I've noticed is the rear LCD is much sharper than before when reviewing pictures that I've taken! I still haven't found an official list of changes but I'd imagine it supports some of the new Canon lenses that have just been released as well. From what I've read Canon usually does this with their firmware releases although it sounds odd a brand new one off the shelf had the latest unreleased firmware.

Hope this helps in some way..

Troy
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Old 24-12-2008, 07:28 PM
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Hi Troy.

My 40D already had 1.1.0 firmware installed.

Thanks anyway, Troy.
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