Uncalibrated mirror?

[ana_lopes1]

<p>Hello, everyone.<br>

Despite not being a particularly demanding amateur in Film photohraphy, I couln't help but to be bothered when a friend saw my most recent photos (I hadn't taken any in over a year) and said "Would you mind me asking? Is the blurryness on the film or did it happen while scanning?". He mentioned the mirror might be uncalibrated, sometimes even a small bump will do that.<br>

I allways thought it would have to do with the grain of the film (though fine) not being the same as digital and the fact that my scanner was quite cheap. Not owning a mangnifying glass yet and not trusting my own eyes, I'd like to hear the opinion of some well eye-trained "Photonetters".</p>

<p>I have four photos for comparison. All taken with a Canon EOS 300X and scanned with an HP Scanjet G3010 using Vuescan at a 2400 resolution and sized down to 25% with Gimp. Ektar was scanned with the Ektar color options of Vuescan, all Fuji slidefilms scanned using the Generic option with Either Automatic Balance or White Balance (which on most ocasions seems pretty much the same to me).<br>

Fuji Provia 400X, shot with ISO 400; Lens: Canon EF 28mm 2.8, Apperture 11<br>

http://img59.imageshack.us/img59/445/apx7.jpg<br>

http://img210.imageshack.us/img210/9210/apx13.jpg</p>

<p>Fuji Velvia 50, shot with ISO 50; Lens: Canon EF 28mm 2.8, Apperture 2.8<br>

http://img718.imageshack.us/img718/5228/velvia23.jpg<br>

(am I insane or does the last photo look sharper than the ones taken with apperture 11?)</p>

<p>And considering it might also have something to do with the lens itself, here's a foto taken with a Canon Compact Macro 50mm 2.5 and an apperture of 2.5, although with Kodak Ektar film:<br>

http://img35.imageshack.us/img35/6105/ektar1.jpg</p>

<p>I'm aware that the differences in the films can make a comparison difficult, but any pointers you can give me will be very much appreciated!</p>

 

[les_gibbons]

<p>are these as scanned or after processing? all look as though a tweak in sharpening is needed.<br>

I find my film scans need more sharpening than digital files.</p>

[ana_lopes1]

<p>These are as scanned, totally unprocessed, except for the reduction to 25% size. Is it normal needing to sharpen film-photos?</p>

[SCL]

<p>They are all unsharp in my humble eyes' opinion. Anything digitally produced generally requires some post processing sharpening unless you automatically sharpen during the scan.</p>

[philip_wilson]

<p>Ana - hard to say from the images exactly what the problem is. ISO 400 film does scan softer than ISO 100 or ISO 50. I personally do not use provia so the only 400 ISO film I scan is Pro400H (print film). I do scan lots of Velvia however. From these compressed images it is difficult (for me) to say where the issue is from. The last two images are sharper than the first two images and the last image has lots of dust on the scan.<br>

I do not know the scanner and do not personally use flat bed scanners but I am not sure about what you mean when you say the mirror is uncalibrated or has a small bump in it. I was not aware that flatbed scanners contained a mirror and the DSLR mirror has no impact on image quality as it is not in the image when the shot is taken. (The only exception to this is a pellicle mirror camera like the EOS 1NRS or EOS RT).<br>

It is often easier to see the issue when you examine detailed crop rather than heavily compressed files however this looks like a focusing issue. The scanner needs to focus on the film to get a good sharp image - two problems exist when this is done - first the scanner AF does not work perfectly - my Nikons are very good - about 98% of the time AF works fine but for a few images I need to use the manual focus option. The second focus issue with a scanner is due to the film not being flat - this results in some areas of the image being out of focus as the scanner needs a completely flat film plane to operate. Usually this is more of a problem with medium format films where glass holders can be used to keep them flat. With 35mm the problem normally occurs more with print film rather than slide as some labs tens to curl the print film when they sleve it. If I have curled 35mm film I leave it squashed at the bottom of a large pile of books for a week or two to get it flat before I scan.<br>

Since I was actually scanning shots this morning I will post an image and a crop of a shot taken with Velvia 100 and scanned on a Nikon 9000 at 4000dpi. This is unsharpened and has only been compressed in photoshop for on screen display. I shot was taken with an old Canon F1 and the 35-105 F3.5 zoom lens probably at F3.5. This was a good lens but not a great lens by any standards so the image is not as sharp as some. Still you can see the detail that film can capture. I find that scanned 35mm film resolution is not as good as my 5DII (21 MP) but is better than my 1DIIN (8.2 MP) - the images do have a different look. this is consistant with most reviews where film is generally equated to about 10 - 12 MP digital (Black and white film can be much sharper as it has very small grain).<br>

Here is the shot I just scanned</p><div></div>

[philip_wilson]

<p>here is an extreme crop to show what you should be able to get from a good scan. this shot was not selected for aesthetic reasons - it just happened to be the last of the five I just scanned. It has been converted to a JPEG and heavily cropped and compressed. The scanned TIFF is 55 MB and 5367 x 3583 pixels. The crop of his hair is from above the left eye and shopws the detail in a 35mm scan - as you can see it is not completely sharp and looks different from a digital image. This crop is 462 x 344 and thus is a very extreme crop. It is equivalent to 0.82% of the image area. On my screen it shows about 7 inches wide so on this scale it would give an 81 inch (i.e. 6.75 feet wide) wide print!</p><div></div>

[ana_lopes1]

<p>Thank you very much, Philip, for a very helpful message!<br>

First off: I'm very aware of the amazing amount of dust on my Ektar shot - I was overly-eager to scan something and did it before looking for my anti-static cloth. I have yet to redo those scans. ;)</p>

<p>From all you've said, I'm pretty sure the problem lies on the bending of the film stripes! I just compared the films and my Ektar is pretty straight, while the Fuji slides are visibly bent in lenght! I allways get them unframed and now I'm wondering if framing would do any good when it comes to scanning... I'll have to try your trick with placing them on a flat surface with a weight on it in the meantime.</p>

<p>About the mirror: the mirror my friend mentioned wasn't a mirror in the scan (flatbeds don't have any, you're right), it was the mirror in the camera; and the bump wouldn't be a bump in the mirror, it would be the camera taking a hit and putting the mirror slightly out of place (I was unclear on that point, sorry). I assume he was trying to imply a mirror that is slightly out of place would induce the lens to focus in a deceiving way, only seeming focused through the viewfinder. I'm not sure how much sense that would make, I'm allways a little doubtful when my friend starts with technicalities, seen as he's more of an aficcionado - he buys oldies, he buys lenses, cameras, he tries everything only once and never has anything to show for; lots of theory, little practice. That's why I decided to ask you pros. ;)</p>

[PuppyDigs]

<p>The SLR's main reflex is semi-transparent, allowing light to past through and bounce off 2 secondary mirrors and a secondary image formation lens before striking the AF sensor at the bottom of the mirror box. If anything is slightly off focus, it is most likely to be the secondary image formation lens, not the mirrors as they are optically flat. If a mirror is out of alignment the image doesn't get to the AF sensor and the camera refuses to focus.</p>

<p>However your scans look okay. Just need the usual adjustments. Even a skillfully applied drum scan never looks as good as the original chrome. All scans need sharpening, color and level adjustments to look presentable. </p>

[philip_wilson]

<p>Yes the mirror in the camera can cause vibration that will effect the shot. usually this is only an issue with longer exposures (Medium format SLRs suffer more as the mirror is bigger). You can lock the mirror up and use a remote release and tripod in these situations. I do not know the EOS 300 but most EOS SLRs have a mirror lock up in the custom functions - check your manual. The 1 series film bodies (e.g 1NRS, 1V ) have it as custom function 12 for example.<br>

Puppy is alos correct that there is a second AF mirror located beneath the primary mirror (which is semi transparent). I guess it can be moved off axis bit as Puppy says this would probably result in no AF. In 13 years of shooting EOS bodies I have never had a problem like that.<br>

In this case the softer edges looked like a film that had curled. Getting slides mounted depends on how they scan best on your scanner. Personally I get E6 developed by a lab and have the 35mm slides mounted (either by them or I do it myself) for medium format i have it cut and sleeved.</p>

[ana_lopes1]

<p>Thank you, puppy face. If the camera wouldn't focus at all with the mirror out of place, then I'm sure the mirror is fine: the pictures looked very sharp and focused through the viewfinder and the AF worked very well - except with the wide angle lens, which gets lazy with AF in low lighting conditions, but I think I've learned enough from this site to know that not all lenses focus equally fast in different lighting conditions, and seen as the Macro lens allways focused quick and sharp, I lean towards the lens itself.</p>

<p>Phillip, alas, the Canon EOS 300X has no mirror lockup. It was one of the things that made me wince when I bought the camera, but I allways keep in mind that I'm not into long exposures and very detailed macro photography... yet. :) Still, I hardly think the mirror vibration would be an issue with focus lenghts from 28 to 50mm and shutter speeds ranging from 1/250 and 1/4000 - I shudder at shutter speeds below 100mm, but I allways keep in mind that on-camera flash is awful and take any good outcome under that shutter speed as a bonus. :)</p>

<p>Well thank you, everyone, you were all very helpful as usual :)</p>