Jump to content

Why don't modern day film scanners use digital camera sensors?


Recommended Posts

  • Premium Member

Well modern scanners need global shutter imagers because the film travels so fast and each image needs to be perfect. So that limits the type/kind of imagers you can use to specialty ones. 

Also... Arri does use their imager in a scanner, the Arriscan. You can buy one, they aren't very expensive anymore and they're still considered one of the best machines (color wise) made. The problem is they're large, slow and there is little to no support. At least with a Scan Station or Kinetta, there are a lot of off-the-shelf parts and you're dealing with software issues mostly, rather than 100% proprietary components. Also, with the lower-cost scanners, there are simply more of them out there with people having to support them. Once all the Arri techs have retired who worked on those scanners, there won't be anyone who knows how to get them working left. 

The 6.5k imager on the Scan Station and Kinetta is very good. It has plenty of dynamic range. In fact even the IMX 4k Sony imager on our FilmFabriek has impressed us greatly. Stuff that's totally blown out on the histogram is easily recoverable in post, even with a 10 bit scan. With a 16 bit scan, it's even better. 

All of that to say, modern scanners do have very good imagers and honestly, film doesn't have nearly the dynamic range in the blacks as digital does, but film has A LOT more dynamic range in the highlights over digital. So you kinda have to scan film in a sweet spot on the scanner to get it right. Once you know that spot, just scan everything there. 

Link to comment
Share on other sites

I had checked with Arri a couple months back. They said their scanners were 1/3 million $. But maybe you are referring to old Arri scanners or we are discussing different machines.

Yes you are correct about the highlights. With the Retroscan 2K the highlights get blown very easy and no recovery. No sweet spot to speak of. I've settled on rescanning for highlight exposure only on some troublesome films. It seemed to me like a camera sensor would have been able to deal with the range. That is why I asked the question.

From what I recall, I thought you had mentioned in another post your FilmFabriek was producing kinda hazy scans. Did you find out what was the issue? Or do I have the facts wrong? If it is producing top notch scans...send some in. We should have an archive here of the quality of scans these machines produce.

 

Edited by Daniel D. Teoli Jr.
Link to comment
Share on other sites

  • Premium Member
2 hours ago, Daniel D. Teoli Jr. said:

I had checked with Arri a couple months back. They said their scanners were 1/3 million $. But maybe you are referring to old Arri scanners or we are discussing different machines.

Well yea, new they're very expensive. Used they aren't too much, $50k at most. 

2 hours ago, Daniel D. Teoli Jr. said:

Yes you are correct about the highlights. With the Retroscan 2K the highlights get blown very easy and no recovery. No sweet spot to speak of. I've settled on rescanning for highlight exposure only on some troublesome films. It seemed to me like a camera sensor would have been able to deal with the range. That is why I asked the question.

Well Retroscan is too low cost to have a decent camera. The one used in my scanner is a bit north of $3k just for the imager. I'm not sure how the Retroscan imager works, but I doubt it streams DPX files to the drive. I can't imagine how low quality that imager must be to get the price down so low for an entirely custom scanner. 

2 hours ago, Daniel D. Teoli Jr. said:

From what I recall, I thought you had mentioned in another post your FilmFabriek was producing kinda hazy scans. Did you find out what was the issue? Or do I have the facts wrong? If it is producing top notch scans...send some in. We should have an archive here of the quality of scans these machines produce.

Oh hazy? na never hazy. We've only had 2 issues. The first is that the system doesn't have optical registration. So the gate needs to be re-designed. I was able to get a prototype gate from them in order to machine it to the specs that will work. So hopefully soon I can do that and it will help with the registration issue, which isn't bad. It's no different than a Spirit or standard ol telecine when it comes to registration. They are fixing that through post stabilization (during transcode) in the new software, which should be out later this year. The only other issue, really isn't an issue... it's more of a complaint. The camera is a bit on the soft side. It's a very good looking camera, but when you zoom into the image, you don't see the crispness of the film grain like you do on a Scan Station. It's either the lens OR the camera, but something is softening the image a bit more than it should be. Mind you, this isn't a horrible issue as the system only does narrow gauge formats AND... most critically, it looks great. The film grain is basically hidden, which is a benefit in terms of looks. But I just expected a 4k scanner to be a bit 'crisper' film grain wise, even if there isn't ANY resolution to be had. We've done a few resolution tests, shooting them and scanning them, but my chart only goes to 800 lines and it does that fine. So I need to get a new chart that will go higher so we can do a test. 

IDK if you saw the last film we made using the scanner, but here it is: 

 

  • Upvote 1
Link to comment
Share on other sites

  • Site Sponsor

Here is the "latest /greatest" sensor that companies are using in film scanners:

https://www.sony-semicon.co.jp/products/common/pdf/IMX342LLA_LQA_Flyer.pdf

6.5K 12-bit Global Shutter.

A machine vision camera and high speed frame grabber with this sensor will run about $7.5k-$8K

You cannot use a rolling shutter sensor for continuous motion film scanners like Xena ScanStation etc. it has to be Global.

For intermittent scanning (Step Frame-scan-StepFrame etc.) you can use a rolling shutter.

Here is a 14K sensor:

https://www.sony-semicon.co.jp/products/common/pdf/IMX411ALR_AQR_Flyer.pdf

Figure $16-20kK for that camera.

  • Like 1
  • Upvote 1
Link to comment
Share on other sites

18 hours ago, Robert Houllahan said:

Here is the "latest /greatest" sensor that companies are using in film scanners:

https://www.sony-semicon.co.jp/products/common/pdf/IMX342LLA_LQA_Flyer.pdf

6.5K 12-bit Global Shutter.

A machine vision camera and high speed frame grabber with this sensor will run about $7.5k-$8K

You cannot use a rolling shutter sensor for continuous motion film scanners like Xena ScanStation etc. it has to be Global.

For intermittent scanning (Step Frame-scan-StepFrame etc.) you can use a rolling shutter.

Here is a 14K sensor:

https://www.sony-semicon.co.jp/products/common/pdf/IMX411ALR_AQR_Flyer.pdf

Figure $16-20kK for that camera.

How much stops of dr does these sensors realistically have? Especially when compared to the DFT 4k and sdc2000. I know a lot of them can do multi pass hdr but I'm curious how these sensors stack up to the dft and sdc without the helpings of hdr. And how is the resolution from these bayer sensors compared to true rgb ccd sensors of the scanity and dft 4k?

Link to comment
Share on other sites

  • Site Sponsor
1 hour ago, Jack Jin said:

How much stops of dr does these sensors realistically have? Especially when compared to the DFT 4k and sdc2000. I know a lot of them can do multi pass hdr but I'm curious how these sensors stack up to the dft and sdc without the helpings of hdr. And how is the resolution from these bayer sensors compared to true rgb ccd sensors of the scanity and dft 4k?

I have a DFT Spirit 4K and the new 6.5K sensor based Xena I have has better performance in terms of detail noise performance and steadiness. We have client who prefer the scans from the 6.5K Xena to Scannity scans for OCN.

The SDC2000 Spirit is a very old and superceded telecine which does not even scan at 2K.

  • Like 1
Link to comment
Share on other sites

  • Site Sponsor
6 hours ago, David Mullen ASC said:

Not sure if someone mentioned that a scanner doesn't need to use a Bayer color filter array and then demosaic the image, it can create RGB color in three passes for better quality & resolution per channel.

A number of currently available scanners do and with the newest sensors, it is just a hit in speed and there is high demand for quick turnaround times on film scanning.

The theory is that with enough pixels a CFA Sensor can make the equivalent of a real RGB sequential scan and I think that is somewhat true especially with 2X and 3X resolution oversampling. The issue is the CFA lenses are imperfect and there is allot of cross-talk between color channels compared to a sequential RGB scan so that crosstalk is worked out with math in the scanner software.

All that said there are customers we have that prefer the scans coming out of the new 6.5K sensor based Xena scanner we run to scans from the Spirit 4K or Scannity which are true RGB.

Edited by Robert Houllahan
Link to comment
Share on other sites

  • Premium Member
18 hours ago, Robert Houllahan said:

All that said there are customers we have that prefer the scans coming out of the new 6.5K sensor based Xena scanner we run to scans from the Spirit 4K or Scannity which are true RGB.

They're crisper, more stable and over-all, just a better scan really. True RGB is cool and fun, but it only really works if the mechanics and optics to back it up are as good as the line array themselves. I just don't think they are. 

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...