Posts

Showing posts with the label adox cms 20

Zen and the Art of Camera Scanning

Image
My article   Zen and the Art of Camera Scanning or The Brief History of Vlads Test Target  is now live on 35mmc.com

Type 120 Positive Test Target PO69

Image
Here is more details on new Type 120 Positive Test Target PO69. This is exact reversal of the Negative Test Target NG69.   The note from Vlad:  The reasons why I started offering the Positive Test Targets are as follows. Everyone who used negative targets while viewing images in the digital camera have encountered the strong hallo around target's bars and stars. That's because camera sensor averages the brightness of the scene and sets certain exposure values. Given that most of the image is almost black (in case of negative) the camera brings brightness up until black areas look gray. That means that transparent areas with bars and numbers are getting overexposed (they basically end up being in Zone 0) . That forces operator to manually step down camera to avoid those overexposures .  Still the halos remain the issue and interfere with the focusing. With positive targets the i ssue will go away - the sensor reads mostly transparent areas, the averaging will lead to whites bei

Using Vlads Test Targets to Fine-Tune Film Scanning Rig

Image
Part 1. Using Vlads Test Targets to Fine-Tune Film Scanning Rig So you decided to scan your film yourself. These days this  is quite a common and wise decision. You either decided to convert the priceless shots in your film archive or you just started your journey as a film photographer and want to share your best (and worst :-) ) shots with friends and mentors. You have to convert your film shots into digital form and be able to share them with a  click. The task is not new and since at least 20 years ago was widely available everywhere - from chain pharmacies to professional photo labs.   The option to save money has always existed  - you would buy your own scanner and off would you go. Many folks went that route and got lost. The time it would take to scan a few frames or a roll of film was anywhere from 10 minutes to hours. Paying extra 7-10 bucks for scanning was no longer such a costly proposition.  Fast forward to present times.  The landscape has completely changed. Photo Labs

How to Use “Vlads Test Target” for Camera Scanning

When scanning film with a digital camera there are only two absolute musts in regards of captured image: it  should be uniformly sharp and focused from the edge to the edge.  Those two qualities can only be achieved when:  the film holder is absolutely parallel to the camera's sensor plane (and keeps film absolutely flat) and you need a lens which is capable of faithfully reproducing your image at 1:1   scale ( or around that value depending on the camera sensor size and film format)    The first requirements can be achieved by carefully positioning and fine-tuning the camera so that when the image to be captured is in focus, it neatly fills the camera frame, and the center and all the corners are equally sharp. The "Vlads Test Target" (Google it!)   has been designed specifically to allow visual control and the best alignment detection. The Vlads Test Target film strips are so sharp that even the slightest loss of focus causes image edges in the digital camera to b

How I use Vlads Test Target for camera scanning

Image
So here is my scan rig tuning workflow if anyone cares: Aligning camera and film holder with the  Vlads test target as generator of the test image. The picture is to grab you attention. I used to see it often on my TV when I was 7 years old and was waiting to watch my favorite animated movies which would open the broadcast at 4 o'clock Moscow time . Prepare your scanning rig - whether it's a copy stand or camera bellows with vintage film holder from Nikon, Canon, Minolta, etc. I will assume that camera and lens are able to slide forth and back in relation to a film holder. Ideally you should use micro-focusing rail. Having Arca-swiss clamp sliding on the rail is possible but you will discover that when you start tightening the clamp once focus is achieved, the image will jump by 1-2 mm - pretty significant and irritating shift given overall frame size.    Keep the film gate empty. Adjust lights, mask out stray light, optionally tether your camera to the computer and connect you

In search for the Holy Grail of Film

Image
To successfully assess DSLR scanning capabilities I needed 35 mm film which would not be outresolved even by the high-end  digital camera. Of all the chart pieces the real drama happens right there - in parlance of USAF 1951 - at Group 0 (zero). Say, if Group 0 Element 5 to be resolved, the lens +film resolution should be at least 87 lp/mm (calculation are based on my USAF targets dimensions and the shooting distance/lens focal distance). Just think of it - you are in front of a chart 24x36 inches (60x90 cm) at normal viewing distance - say two feet - will you be able to see the strokes of size 0.3 - 0.5 mm ? If your vision is 20/20 you probably will, but barely. The same is true for the camera as we will see below. So what film we should use and how to get it? Even if film+lens give us say 90 lp/mm what your digital camera will be able to capture? Read on... Even half a year ago, I was not familiar at all with the films sold nowadays in American stores. In B&H and Adorama prominen