drum scan versus Canon FS 4000 + Vuescan

Dear all,

 

I have been using the Canon FS4000 US together with Vuescan happily for a

while now. I recently shot a nice close up of a swan and was surprised that

the scan seemed noticably less sharp than the slide. I never noticed this

before. To check, I had the slide scanned professionally using a drum scan

(yielding roughly the same sized file). Again, the drum scan was much sharper

and showed significantly more detail. Is this to be expected when comparing a

professional drum scan with a commercial scanner? Could it be that my scanner

needs toubleshooting? Or should I be using the Canon software instead of

Vuescan? Any help would be appreciated.

 

Cheers,

joel

Hi Joel, I use that scanner as well. Can you open both images in Photoshop as two layers (try to roughly align them- you may need to make one layer temporarily less opaque to do this), zoom to 100%, make a selection at a key area where you think one is more detailed and crop both identically? Then save each as a jpeg and show us the difference.

 

Some drum scanners automatically sharpen when they scan. Vuescan does no sharpening and for slides with the FS4000US I highly recommend using PhotoKit Sharpener's Capture sharpen and then output sharpen for maximum quality.

 

For slides, stay away from the Canon software.

<i>Is this to be expected when comparing a professional drum scan with a commercial scanner?</i>

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Short answer: yes.

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Long answer: Drum scanners use PMTs which inherently sharper then CCDs. That, and their optical system is considerably sharper. This is easy to do since drum scans are one pixel at a time, as opposed to one line at a time with a flatbed scanner. Finally, fluid mounting film to a curved drum surface does two things for sharpness. First it holds the film in the exact plane of maximum sharpness. Sharpness is uniform edge to edge in any direction. Then, the fluid used in mounting the film to the drum fills in the scratches and imperfections in the film surface (front and back both) which visibly improves smoothness of tones. This too acts as a visual enhancement which may be interpreted as improved sharpness.

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Full disclosure: I'm a drum scanner operator, just so you'll know.

Also keep in mind a projected or backlighted image generally may look sharper than it really is, just as an effect fo the way our eyes see things.

Hi: Is this to be expected? I do not disagree with Bruce Watson but do not think the issue is one of absolutes. A car that can go at 300 mph is indeed faster than one that can go at 290 mph, but that only matters in a race. A good drum scanner will produce sharper images but my 4000FS produces very sharp images from 35 mm, good enough for excellent enlargements to 16X20. The drum scan you are comparing was fluid scanned and the scan from the FS4000 was a dry scan. You can take it as a given that in dry scans the film is never flat and that will affect focus. Also, dry scanning subjects the image to light scattering and reflections at the film grain, that do no occur with fluid scanning. That however can be remedied by fluid scanning with the FS 4000. In www.wetmounting.com you will see a sample scan on the FS 4000 dry and fluid mounted also using Vuescan. There is a difference. In comparing drum scanners with others, a valid comparison requires that both be fluid scanned. This can be done on the FS4000. I do not know that your own FS4000 is identical, and guess that a good drum scanner will still yield better results, but here at least you have an indication of what the difference is between dry and fluid scans. The 290 mph car will not win the race but will it matter? Only you can answer that.

 

Julio

www.scanscience.com

Joel,

 

First of all, congrats on that dramatic image! You captured some great light and a really cool pose on the swan.

 

Anyhoo, back to the FS4000... I have been using, testing, tweaking, and pixel peaking with my FS4000 and Vuescan for a couple years now; and have a pretty good sense of its capabilities and limitations. If everything is working properly, this scanner really does deliver detail comensurate with the advertised 4000 samples/inch. And to answer the one question, no, going back to FilmGet is not likely to give you any increase in detail over Vuescan.

 

When comparing scans of my sharpest slides with what I can resolve looking through a high powered microscope, I find that there is just the tiniest bit of extra detail on the film which the FS4000 scanner was not able to resolve. You really have to look hard to find this difference though! It is certainly true that a high-resolving drum scanner operated to the best of its capabilities will be able to wring out this last bit of detail from the film. However, it is almost splitting hairs to talk about this level of resolution. For me (an admitted pixel peeper) the drum scan wouldn't really be worth it just based on resolution alone.

 

Where you WOULD really expect to see improvements, and where the drum scan can really shine, is in terms of shadow details - i.e., being able to extract information from the darkest parts of the film. The FS4000, like most desktop scanners doesn't really have quite the dynamic range to take full advantage of all the information there is in a contrasty slide. At least not in a single scan, anyway. The scanned shadow areas tend to appear devoid of the detail and color that the eye sees in the slide, and may even appear noticeably noisy (particularly when levels/curves adjustments are made in post processing). This of course can be corrected to a large extent by scanning at two different exposures, then combining. Its a lot of extra work, but it can be worth it if you have a great image which deserves the extra attention.

 

But back to the reduced sharpness you are seeing in that image, I can think of a few things to check, all having to do with focus settings:

 

First, see just how flat the film is. If the scan is of a mounted slide (or even if it isn't), it might be worth trying to set the focus point in Vuescan to somewhere about halfway between the center and one of the edges. This helps to compensate for bowed film. As long as you don't go too far towards the edge, it should enable you to get the image sharp everywhere in the frame.

 

Another thing I like to do is insure that the focus location point in the Vuescan preview is not in a very dark region. I have always wondered if the scanner would see enough signal to effectively determine the best focus when you place the focus point in a dark region. (Having said that, if the FS4000 actually uses the IR channel for focus, then this wouldn't be an issue so you could just ignore this idea).

 

Also check that you don't have any grain reduction selected (on the filter tab).

 

Finally, check what you have set in the Auto focus box on the Input tab. I usually select "scan" or "always" to insure that the scanner actually tests for focus at the beginning of the actual scan (not just the preview). With "manual" or "preview" selected this won't happen.

 

As for wet scanning with the FS4000, that would clearly give you superior results if you can make it work. I have to be honest, I tried Julio's wet scanning kit for this scanner but was never able to get it to work effectively. Still I would be very interested to hear any tips from anyone who has.

 

Hope you figure it out, and it turns out to be something simple!

 

Jeff

Good stuff, Jeff. I just wanted to say that it's nice to see someone else who knows how to drive their FS4000 with Vuescan. It's an awesome combination.

Agreed, FS4000 and (some versions of) Vuescan's quite good. Jeff's comments on focus are spot-on. I added folded over strips of scotch tape to the inside of my strips holders to keep them a bit firmer.

 

Make sure the focus point is on an area with some detail and contrast (not flat black or pure light) or AF won't work well.

 

If you're losing shadow detail in a slide, consider scanning at 2 exposures and combining them manually, in a program like Photomatix, or by using the new version of Vuescan (can't vouch for this method as I'm sticking with 8.3.75).