Jump to content

Poor scans - May explain why some switch to Digital


Recommended Posts

 

<blockquote>

<p ><a href="../photodb/user?user_id=3995956">Mauro Franic</a> <a href="../member-status-icons"><img title="Frequent poster" src="http://static.photo.net/v3graphics/member-status-icons/3rolls.gif" alt="" /></a>, Mar 27, 2009; 08:34 a.m.<br>

Lex, if you want to, you can send me a Kodachrome slide to run through the 9000 to see the results. I've never seen any ghosting.</p>

</blockquote>

<p>Mauro, it would be interesting to know but I fear that would lead me to wanting a 9000 and there is no way I'd get that past the financial controller (read wife) at this time. Thanks for the offer though...</p>

<p>Rishi, don't forget the contents page when you start part 2 :-D</p>

 

Link to comment
Share on other sites

  • Replies 799
  • Created
  • Last Reply

Top Posters In This Topic

<blockquote>

<p ><a href="../photodb/user?user_id=4927583">Federico Calboli</a> <a href="../member-status-icons"></a>, Mar 27, 2009; 07:50 a.m.</p>

 

 

 

<p>1) the stalks and leaves of whatever plant the yellow flowers are, in the left side of the picture</p>

</blockquote>

<p><br />Frederico, thanks. The flowers are canola, lovely bright yellow fields in early Spring.</p>

Link to comment
Share on other sites

<p>Lex, beautiful scan, I must say. And beautiful photograph!</p>

<p>Pepper grain is definitely there even in your 35mm scans -- I dunno, maybe I'm just trained to see it -- but it's the first thing that pops out at me on any Imacon scan. Not as visible on prints unless you print big.</p>

<p>Also, fluorescent tubes don't automatically mean you have a diffuse enough light source... in fact, you most certainly don't. My Minolta has a CCFL, and without the 'grain dissolver' or the Scanhancer, I still see pepper grain as well as anti-newton glass etch.</p>

<p>Finally, how'd I get the job of starting the new thread? Haha, honored though :)<br>

Cheers,<br>

Rishi</p>

Link to comment
Share on other sites

<p>i want to second what Sergiy Podolyak has been saying and why i started my photography hobby with digital slrs and, after being "forced" to use film for a few months (digital camera stolen in Ecuador), switched to film. the colors in film are just incomparable to digital. the color texture is beyond what digital can produce, at least for the time being. without being a master of photoshop doing all kinds of gimmicks to a digital file one cannot come even close to what film has after development. here is an example, scanned with very (8 years) old epson flatback - nikon fm10, f/1.8 50mm at 1.8, 1/125, fuji reala 100.</p><div>00StHz-119861584.thumb.jpg.5534c9de715cd5ed70aff640ccbe6bb9.jpg</div>
Link to comment
Share on other sites

<p>Lex, since you've got an Imacon there and have taken it apart, have you noticed if the Peltier element is attached directly to the back of the CCD? Can you see it? I think there's some plastic of significant depth behind the CCD in my Minolta scanner, but was wondering if attaching a small Peltier element would eliminate the need for multi-sampling + give me better shadow detail...</p>

<p>Thanks,<br>

Rishi</p>

Link to comment
Share on other sites

<p>When doing a resolution performance comparison, why would you use a Nikon Coolscan 9000 to do the scans? It is clearly not the best tool by which to capture all the detail in a film image. A drum scan is well known to be the best reproduction method, but also the most expensive, with the hassle of ordering and waiting for the scan. Most of us are not willing to do that on a large percentage of our images, hence the DSLR! The DSLR reperesents extreme convenience and practicality. Perhaps you may get a slight resolution advantage from film if you're willing to pay the money, but just how many of your images do you in fact print larger than 20x30"??? Because full frame DSLR w/professional lens, tripod, etc, does that without breaking a sweat. That settles the dilemma for me. I've had images from even my Canon Powershot S70 published double page in a national magazine. We really should spend more time out in the field MAKING images, rather than bickering over microscopic details of quality. Jut my two cents, -Clayton </p>
Link to comment
Share on other sites

<p>When doing a resolution performance comparison, why would you use a Nikon Coolscan 9000 to do the scans? It is clearly not the best tool by which to capture all the detail in a film image. A drum scan is well known to be the best reproduction method, but also the most expensive, with the hassle of ordering and waiting for the scan. Most of us are not willing to do that on a large percentage of our images, hence the DSLR! The DSLR reperesents extreme convenience and practicality. Perhaps you may get a slight resolution advantage from film if you're willing to pay the money, but just how many of your images do you in fact print larger than 20x30"??? Because full frame DSLR w/professional lens, tripod, etc, does that without breaking a sweat. That settles the dilemma for me. I've had images from even my Canon Powershot S70 published double page in a national magazine. We really should spend more time out in the field MAKING images, rather than bickering over microscopic details of quality. Jut my two cents, -Clayton </p>
Link to comment
Share on other sites

<p>Scott Wilson wrote:<br /> "But tonality is not the same as color rendition, if it were then no B/W print would have good tonality, but this is clearly not the case. Tonality is the ability to see small changes in either color or brightness in a photo."<br /> <br /> <br /> Rishi Sanyal wrote :<br /> "Yeah, um, Sergiy's comment was entirely irrelvant, Scott. I'm surprised you deigned a response :)"<br /> <br /> <br /> How do you, Rishi, know? To claim that my comment or question is "irrelevant", meaning that in digital photo-sensors tonality (gray scale resolution) is nothing common with proper color representation, - to claim that You have to know EVERYTHING about digital sensors. <br /> Ok, everything is possible, but I put AGAIN my quotation from a person, who put his life on digital cameras:<br /> "Ken Kryda , Nov 24, 2008; 05:22 a.m.<br /> <br /> "I've been designing digital cameras for about 30 years now, including the first 2 Leaf camera backs, and film scanners for Associated Press and most recently, on the opposite end of the quality spectrum, camera phone sensors and image processors at Micron....<br /> I've also developed a high dynamic range, hyper-spectral printing process using an HP 3100, rip engine and 2 layer transparencys with a xenon arc light source( 30cd/m2). The color was measured with a Spectroradiometer and found to be the exact same as the real scene in nature. The images were captured with a Canon DS MkII (14 exposures). So, I'm pretty confident you can get the same color quality with digital but it may be more work than just pressing a button."<br /> You see? You have to make 14 exposures (bracketed, read "to build proper linear gray scale") to build proper MEASURABLE-CORRECT color representation in digital. <br /> If you see color distortions in digital, as in the case of Komatsu shot, you can be sure that grayscale of a sensor is distorted. They are independent in film or photo-paper, but are highly dependent in digital sensors or digital printers. <br /> So, Rishi, until you will know EVERYTHING about digital sensors, please dont claim that my comment or question is "irrelevant".</p>
Link to comment
Share on other sites

<p>For photographers, who have never seen PURE YELLOW Komatsu machines:<br>

http://upload.wikimedia.org/wikipedia/commons/c/c3/Wheel_Excavater_Hanomag_Komatsu_001.jpg<br>

Today I took some shots of dirty Komatsu excavator just across the street by Olympus 720-SW, 7.1 MP, no levels, no color manipulations, crop only.<br>

Machine on the right - BAUER - it is yellow-orange.</p><div>00Stdc-119993584.jpg.9a27e9366be9853d10ac9e0dc12fc655.jpg</div>

Link to comment
Share on other sites

<blockquote>

<p ><a href="../photodb/user?user_id=2381463">Rishi Sanyal</a> <a href="../member-status-icons"><img title="Frequent poster" src="http://static.photo.net/v3graphics/member-status-icons/2rolls.gif" alt="" /></a>, Mar 27, 2009; 01:11 p.m.<br>

Pepper grain is definitely there even in your 35mm scans -- I dunno, maybe I'm just trained to see it -- but it's the first thing that pops out at me on any Imacon scan. Not as visible on prints unless you print big.</p>

 

</blockquote>

<p>Rishi, I do see it sometimes to varying degrees in my 135 Provia scans but generally it's reasonably subdued, only visible at 100% in a 6300ppi scan, and usually doesn't bother me. What I have found is that the degree of visibility of this "pepper grain" is a very good measure of the sharpness of focus of the scanner. Even though the 646 has auto focus, from one scan to another there are sometimes minute variations in focus, nothing that would affect the final appearance of the scan/print but discernible on-screen at 100% in a 6300ppi scan. If the focus is just slightly off, the pepper grain disappears and the scan softens a tiny amount. To me the effect is very similar to what I see with diffuser vs no diffuser comparisons for other scanners, and even in the 949 brochure itself. To my eye the diffuser softens the scan a tiny but perceptible (at 100%) amount.</p>

<p>But the quick and dirty initial test I did on a scrap piece of 120 Provia showed a massive amount of this grain at 6300ppi. I need to do another test on a different piece of film.</p>

 

<blockquote>

<p ><a href="../photodb/user?user_id=2381463">Rishi Sanyal</a> <a href="../member-status-icons"><img title="Frequent poster" src="http://static.photo.net/v3graphics/member-status-icons/2rolls.gif" alt="" /></a>, Mar 27, 2009; 05:49 p.m.</p>

<p>Lex, since you've got an Imacon there and have taken it apart, have you noticed if the Peltier element is attached directly to the back of the CCD? Can you see it? I think there's some plastic of significant depth behind the CCD in my Minolta scanner, but was wondering if attaching a small Peltier element would eliminate the need for multi-sampling + give me better shadow detail...</p>

 

</blockquote>

<p>The 646 doesn't have the cooler, only 848, 949, 2848 and X5 have it. I have thought about adding it though! The Peltier device sits directly on the back of the CCD package, and heat from the warm side of the Peltier device is dissipated into the bulk of the CCD carriage via a heat transmission plate. Both sides of the Peltier device are smeared with thermally conductive grease to ensure efficient heat transfer. The Peltier is regulated to 18C as far as I know.</p>

<p><img src="http://www.lexharris.net/documents/848_cooler.jpg" alt="" width="563" height="277" /></p>

<p>Now as to whether this very moderate reduction in CCD temperature makes any difference to background noise (i.e. shadow detail) is another matter. And is noise reduction even needed? Consider this example. As you know Imacon scanners mount film on a flexible steel holder with a magnetic sheet. The holder is obviously totally opaque to light, so if the crop that you scan includes some of the holder around the edges, the edges should be totally black, RGB = 0,0,0, yes? If there is noise in the scan, you should see some pixels that are not 0,0,0. OK, here is a scan of 135 Provia with some holder edge included and also the unexposed strip between frames:<br>

<img src="http://www.lexharris.net/documents/SP01-41-18_small.jpg" alt="" width="640" height="406" /><br>

Notice the scan is a little light, this is because I usually set the black point in the image histogram a little below true black so I don't miss any detail (easily corrected later in PS). This makes it an even more severe test. Here is the 100% crop from the rectangle in the top RH corner:</p>

<p><a href="http://www.lexharris.net/documents/SP01-41-18_crop.jpg">http://www.lexharris.net/documents/SP01-41-18_crop.jpg</a></p>

<p>Download this crop, open it in PS and have a look at the RGB values for the opaque mount and the unexposed strip between frames. Zoom to 500% or more if you wish to see individual pixels. In the strip between frames you can see some non 0,0,0 pixels, it is not truly opaque but pretty darn good. In the opaque mount area, solid 0,0,0. There is no electronic noise in truly black areas in this scan. Peltier cooling will not make it any better as far as I can see.</p>

Link to comment
Share on other sites

<blockquote>

<p>Please do not take my questions and explanations here as personal offense or dump critique, it is only a way for better understanding of non-avoidable dead end of electronic cameras. Electronic scanners have much more room for further development because they dont have matrix of pixels, just have ONE ARRAY, they can contain only 8000 LARGE and INDEPENDENT (it is very important) analog-to-digital converters, they have time to properly switch their internal strobbing device between rows and columns ant a hundred another electronically-important reasons. It is no problem for me to explain each of them here.</p>

</blockquote>

<p>Sergiy, I'm interested (seriously) in your view that digital matrix sensors have reached a performance plateau and have nowhere further to go. Can you elaborate further on the technical reasons for this? (start a new thread if you wish, to avoid clogging this one). Please feel free to be as technical as you like. One thing that puzzles me is the "scanner" example you cited (DSLR back on macro copying stand). Is this not a "matrix" type sensor, inferior to the line sensors in scanners? So was this example just tongue-in-cheek or are you seriously proposing that this is a better way of "scanning" than traditional scanners with in-line arrays? Sorry, I can't tell for sure.</p>

<p>My own experience with CCD array sensors and derivatives such as CID arrays in industrial applications over the last 15 years or so is that these devices are limited in dynamic range and no real improvement in dynamic range has occurred over this period. This seems to be consistent which what you are saying so I'm interested to hear more.</p>

Link to comment
Share on other sites

<p>Rishi, oops, I stand corrected, looking harder in the black (edge of mount) area at 800% zoom and with screen brightness turned up there are some pixels at 0,1,0 but at that level I don't think I'll bother with a cooler.... Maybe on a hot summer's day it could make a difference, on a hot day the top of the scanner does tend to get warm after a while.</p>
Link to comment
Share on other sites

<p>Lex, yes I can do what you want by two very different ways:<br /> 1. Start new thread with detailed description of digital sensor design, with explanation how digital camera samples signal from matrix, why it is impossible to get low noise signal while increasing pixel count, and why it is impossible to DELIVER quality signal from inside sensor matrix.<br /> I can show why impossible to build CHEAP sampling system, and how much is really cost good balanced system with wide dynamic range and at the same time high number of pixels.<br /> That explanation can be with numerous datasheets from ADI, TI etc. That detailed explanation will cover 1% of the digital problems. <br /> <br /> OR<br /> <br /> 2. I can tell you only one phrase, which will cover the rest 99% of understanding those problems, BUT it will be the most shocking thing in your entire photo-life. And you could not live without that any longer.<br /> Which one do you prefer?</p>
Link to comment
Share on other sites

<p>Lex, you see, electrons .... they do not love each other.<br>

And this entire world is built on love.<br>

That is why *electronic* digital cameras have no future. Picture on film is formed, built by a group of particles who love the light and love each other, grouping under the light.<br>

Electrons spread as wide as possible from each other.</p>

Link to comment
Share on other sites

<blockquote>

<p>Lex Harris wrote: "Why does repulsion of like charges mean the end of digital cameras?"</p>

</blockquote>

<p>Who needs them? Take a look at computer you are sitting at: main input media (CDR-DVD) is optical, the output device (monitor matrix) is optical, main controlling device (mouse) is optical. Main communication device and connector to the world (inter-net) is also optical. Why do we need that metal noisy dusty electron-ic mediator between all these beautifull OPTICAL devices? Why do we have to convert all our OPTICAL data to and from those nasty electrons?<br>

The future is pure Photography.</p>

Link to comment
Share on other sites

 

<blockquote>

<p ><a href="../photodb/user?user_id=643213">Sergiy Podolyak</a> <a href="../member-status-icons"></a>, Mar 28, 2009; 09:30 a.m.</p>

 

 

 

<p>Why do we have to convert all our OPTICAL data to and from those nasty electrons?<br />The future is pure Photography.</p>

</blockquote>

<p>Ah yes, but what is powering all those optical devices - the flow of electrons. And where does light itself come from - electron energy transitions, incandescence, electroluminescence... yes, electrons are your friends.</p>

<p>Nice joke Sergiy, lots of love and light to you :-)</p>

 

Link to comment
Share on other sites

<p>Lex, Rishi,</p>

<p>

<p>I am surprised that a film scanning would need to have its CCD cooled, you have to figure that the maximum exposure time for any one scan line is going to be on the order of 10ms or so.</p>

<p>Having said that Lex’s scan showing very low noise in the black area might not be all that good of a test. Lex how hot was it the day you did that scan? Scanning at 32C would have a lot more dark current then scanning at 22C.</p>

<p>Still with as short of an exposure time as a scanner has it does seem odd that there would be a need for cooling.</p>

</p>

Link to comment
Share on other sites

 

<blockquote>

<p ><a href="../photodb/user?user_id=940372">Scott Wilson</a> <a href="../member-status-icons"><img title="Frequent poster" src="http://static.photo.net/v3graphics/member-status-icons/1roll.gif" alt="" /></a>, Mar 28, 2009; 10:34 a.m.</p>

 

<p>Lex, Rishi,</p>

<p>I am surprised that a film scanning would need to have its CCD cooled, you have to figure that the maximum exposure time for any one scan line is going to be on the order of 10ms or so.<br>

Having said that Lex’s scan showing very low noise in the black area might not be all that good of a test. Lex how hot was it the day you did that scan? Scanning at 32C would have a lot more dark current then scanning at 22C.</p>

 

 

<p>Still with as short of an exposure time as a scanner has it does seem odd that there would be a need for cooling.</p>

 

</blockquote>

<p>Life is full of surprises Scott! Imacon seem to think cooling worthwhile:</p>

 

 

<p ><a href="http://www.lexharris.net/documents/Flextight_848_brochure.pdf">http://www.lexharris.net/documents/Flextight_848_brochure.pdf</a></p>

<p > </p>

<p >I don't recall how hot is was when I did that scan. The scanner (and me) mostly operate at comfortable room temperature so most likely that scan was done at a moderate temperature. Dark current as you have indicated is a function of temperature, but I'm not sure why you're suggesting a short integration time would lessen any need for cooling. Without knowing the architecture of the device I guess it's all speculation, but generally with CCD arrays I would expect dark current shot noise, photon shot noise and readout noise all to increase with reduced integration times.</p>

<p > </p>

<p >In any case I do not see any significant noise in true black areas in my scans so for me a cooler seems unnecessary</p>

<p > </p>

 

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



×
×
  • Create New...