oben_c

Yesterday I noticed the first speck of dust in the viewfinder screen

after many weeks of much lens changing. I am normally meticulous in

the way I change lenses but on this one occasion it was outdoors in

the wind and obviously something went in.

Well if it had been my OM-3Ti I would have simply taken the screen out

and cleaned it with some puffs of air and similarly with the mirror.

But the 20D's screen is not removable.

So I considered the options and finally came up with the idea of using

the vacuum cleaner to suck out the dust.

I disengaged the 17-40mm on the body and left a small gap between the

body and lens. I brought the vacuum cleaner minus the attachment (ie.

metal tube) switched on closer to the combo and allowed it to suck

close to the edge.

Then I lifted the lens further and used my hand in a cupping manner to

increase the effect of vacuum on the body without getting too close or

risking occlusion.

Lens was screwed back on....

Screen was perfect with no dust. Any one else used this technique and

have I risked my camera in some unforseen way by doing this?

On my calibrated LCD monitor the banding is clearly visible.

I have found the vertical banding in RAW images converted with DPP, C1, and ACR so it does not seem to be a conversion artifact.

There are many theories regarding it but its a real phenomenon and I don't care for it at all.

It really puts a downer on an otherwise acceptable camera.

Hello all,

<p>

Upon viewing another thread in which a central bullseye artifact was

being discussed in relation to filters and photographing aurora

borealis - I noticed a much more obvious but uncommented noise issue.

<p>

My 20D also has the same type of noise as in this picture by "Suman L"

in the darker shadow areas of normal photos.

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You'll see that it affects the entire frame and I think this is a huge

problem as far as the 20D goes... it's really turned me off this

camera despite it's otherwise good (not great) features.

<p>

Here is the photo - <p><img

src="http://www.photo.net/bboard/uploaded-file?bboard_upload_id=20358084">

<p><i>Photo by Suman L demonstrating vertical band noise

Next shootout will be the mythical 35-80mm f2.8 Zuiko vs. the Canon 24-70mm f2.8 - which I'll post in two weeks or so.

Any feedback etc. on how I can get a completely fair test would be appreciated.

Here is the full view from the Zuiko lens. The one above was the 17-40mm full view. Both are reduced to 25% and saved as jpeg (quality 8) - no sharpening on either.

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<img src="http://img.photobucket.com/albums/v431/zuiko/Fullz.jpg">

Here are the 100% crops from the centres and corner/edges. There is a slight difference in image magnification due to movement of the camera to compensate for the different FOV between 40mm and 50mm lens.

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I must say that the 17-40mm is a hell of a lens when compared against the legendary Zuiko 50mm f2 macro - but the corner/edges really show that the Zuiko wins this battle. You can also begin to get an idea of the delicious smooth bokeh that the Zuiko 50mm f2 is reknowned for.

<p>

Both were taken at ISO 100 with mirror lockup and self timer. Both were focussed critically in the centre with manual focus. Camera outputted RAW images which were converted to 16 bit TIF with DPP - cropped in Photoshop CS and saved as jpeg (10 quality). No sharpening - these are straight out of camera shots (EOS 20D).

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<img src="http://blog.candemir.org/centre.jpg">

<p>

<img src="http://blog.candemir.org/corner.jpg">

Here is the full image that the crops were taken:

<img src="http://img.photobucket.com/albums/v431/zuiko/Full.jpg">

Greg,

WOW, thank you for this information. If the results with RAW are unsharpened then the results I am getting are phenomenal and even more breath-taking than what I had imagined!

With the best focussed and steadied 17-40mm L shots I am getting superb sharpness throughout the zoom range. I'm really impressed at the 20D's capability in this way.

The only minus is the dark viewfinder due to 1. the 20Ds smaller pentaprism assembly and 2. the f4 of the 17-40L which I am going to keep on the lens most of the time to avoid dust contamination of the sensor.

To Beau, Shaun and Andrew,

Thanks for the Photoshop tips on sharpening and techniques. I am going to start experimenting soon but I had no idea that the sharpness I was getting was unadulterated by the camera with the RAW format as explained above.

WOW.....

Hi Chris,

The Kindai operates in two ways. Stop down metering (the default) in which one focusses wide open then selects the aperture needed - hence the camera then meters for the available light. I use this way.

Wide open is the other option (a small screw determines which mode the adapter works) where as you say the DOF must be pressed prior to shutter release. Each way has its advantages.

It's a very nifty piece of gear and I'm itching to try my Zuiko 35-80mm f2.8 and comparing the results to the 24-70mm f2.8. (On holiday presently).

It's certainly worth the investment if you have the Zuiko glass already and you'd be surprised at the results. I found my 21mm f2 was not even up to the standards of the 18-55mm as far as CA goes. The Zuiko's CA was apalling at the edges. The 50mm f2 however is simply amazing - I don't have access to a EF 50mm f2.5 macro to compare but the performance of the 50mm f2 would be hard to beat by any lens. I'm certain of it as the images are totally mind blowingly sharp with the 20D. The bokeh is also absolutely wonderful with this lenses f2!

I'll try to post some images soon.

Hi Beau,

I bought the full version of Photoshop CS last week also.

I've played around with it only a little as I'm too busy with the EOS 20D and now 17-40 lens.

What sort of procedure/recipe would I need to know to get the sort of excellent results I see posted here. I've seen the filter gallery and tried those - and have noted the SHARPEN menu in the filters.

I've also seen the Unsharp Mask - but what sort of values do people use to sharpen up their photos without making them look too altered?

Thanks for your help.

Well I bought a Canon G3 2 years ago after many years of using the

Olympus OM Zuiko system. Within a few months the film equipment was

standing by idle as I blazed along with the digital camera.

Last year I heard about and bought the Kindai OM to EOS adapter as an

insurance policy for all the Zuiko glass I have - including such

special lenses as 24mm f3.5 Shift (yes Canon now has one too - but

this was it for about 15 years!) and the legendary and mythical

35-80mm f2.8 Zoom.

Last week I was forutunate enough to get myself an EOS 20D with the

EF-S 18-55 kit. To say I was disappointed was an understatement with

this combo. The images were exceedingly soft - I later discovered

partly because of the default Parameter settings.

Anyhow after this initial shock at the soft images I was able to get

reasonable but still noticeably soft images using the 18-55 and +2 of

Sharpening in camera.

Then I used the Zuiko 50mm f2 Macro lens on the adapter. My oh my....

wow... edge to edge sharpness like I had never experienced prior. It

absolutely blew away the 18-55mm. Note that this lens is considered

better than the legendary Leica 50mm f2 Summicron!

While the Zuiko was fine for deliberate and slow work - I still felt a

need for a fast AF Canon lens that delivered the sharpness that the

Zuiko had demonstrated the 20D was capable of.

I read this forum and visited several shops and tried the 24-70mm L

and found that while a good lens it was certainly a notch below the

Zuiko in sharpness. While I appreciated the f2.8 ability it came at

too great a cost as far as weight went - at 1 kilo - it was going to

be a struggle to really use as an only lens for me anyhow.

I then examined the 17-40mm L lens. Compared to the 24-70mm L I found

that its images were as sharp throughout the zoom range with my

testing (tripod, mirror lock up and self timer). At half the weight of

the 24-70mm I think I've made the right decision with the 17-40mm L.

I did a shoot out with the 17-40mm L against the Zuiko 50mm f2 and you

can guess by now that the Zuiko blew the 17-40mm away but I'm still

very happy with the 17-40 lens and it in turn absolutely blows away

the mushy 18-55mm images by a fair margin.

I would post some samples at 100% crop from the Zuiko but don't know

how in this forum. The sharpness is just amazing - I mean it resolves

the finest detail from corner to corner. Breath taking stuff.

I'm now excited to get the 17-40mm out for some real life use.

Examining the photos it has taken versus the 24-70mm and knowing how

well respected that lens is - I'm very happy with my decision.

Any tips on how I might get sharper images without the +2 in camera

parameter sharpening? I'm using RAW format and am only a beginner as

far as post-processing goes. Thank you all for your time and hopefully

answers.