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Joined: 14 Dec 2006
Location: Los Angeles
|Posted: Thu Jan 03, 2008 1:04 pm Post subject: Resolution, Softness, and Back Focus
Here is an important note released online from Jim Jannard regarding how to get the best quality image (in terms of sharpness) from the RED ONE Camera:
"My bet is that there is plenty of confusion on this issue. Here's my take on how to get the best image from a RED ONE.
1. Back focus needs to be set correctly and checked regularly (depending on amount of use and conditions).
2. Lenses need to be checked if you use focus scales to set focus. Most assume that all PL mount lenses are correct. I assume they are not until I have checked them.
3. All Bayer pattern sensors should have an OLPF which defocuses the image a bit. Sharpening is mandatory somewhere in the chain if you want maximum resolution and sharpness (not necessarily over-sharp to the point of looking like hyper-video)... (see Canon's words on this below). Since we do NO in camera sharpening, it MUST be done somewhere along the line. If you just open a RAW RED file... it will look soft. There are OLPF Compensation options in RED Alert! and REDCINE, but they are mild right now and not automatic. We will add a better set of tools for this soon.
In contrast, most other digital cinema cameras have in-camera sharpening. So if you just open and compare, our image will look soft. Was it the back focus? Or the lens? Or the fact that no OLPF compensation was used? I think a lot of what has been blamed on back focus lately is actually no OLPF compensation. It is very easy to find out. Just open a frame grab in Photoshop, add 300, 0.6, 1 of Unsharp Mask... and you will know right away.
Unless everyone understands this, RED is at a distinct disadvantage for comparisons.
This (below in italics) comes from the Canon manual. If I am not supposed to post this... let me know and I'll take it down. With great respect for Canon, we think they have the best handle on digital stills. Maybe this endorsement will help them relax on me posting a piece of their manual?
Please note. You may choose to leave the 4K image alone with no sharpening because you like the way it looks. That is an option we are consciously giving our customers. There is just more to the story you should know.
Another note... using an OLPF Compensation (sharpening of some kind) does not necessarily take away the "film-like creamy look" of RED footage. If you go way to far... of course it can. But there is a lot of room for compensation before that happens. It might make a good thread just to see what people are having the best luck doing...?"
From Canon 1D MKIII manual:
Regardless of how the camera’s focusing system is set-up, there are aspects of image quality for Canon’s EOS-1D Mark III that need to be established and optimized by each photographer or organization.Particularly for shooters working in a JPEG workflow, the in-camera sharpening levels are vital. Furthermore, even though the EOS-1D Mark III is one of the finest digital SLRs in the world in terms of digital “noise” at high ISO settings, there’s an additional noise reduction setting some users should experiment with.
Anti-aliasing filter and inherent sensor sharpness — EOS-1D Mark III
The EOS-1D Mark III has a multi-layer low-pass / IR-cut filter positioned immediately in front of its CMOS imaging sensor. This filter enhances the camera’s ability to generate proper color, and minimize problems with moire. In doing so, it slightly reduces the apparent sharpness of the image.
To counter this, users need to expect to apply some additional sharpening to EOS-1D Mark III files to optimize the inherent detail in its 10-million pixel sensor, and the lens’s detail as well. This can be done using in-camera sharpening, within whichever Picture Style setting you choose, or alternatively it can be done afterward in the computer.
Suggested in-camera sharpening settings For JPEG shooters:
Picture Style Neutral or Standard > Sharpness level 2 or 3 (keeping it at level 2 will minimize the effect of any noise at ISO 1600 or above)
For RAW shooters (if processing images in Canon’s Digital Photo Professional software): Picture Style Neutral or Standard; Sharpness level 0~3
• If further optimizing images in Photoshop, in-camera sharpness should ideally be left at zero
• If no further image-editing is anticipated, raise in-camera sharpening to level 2 or 3
• For RAW shooters who process in another company’s software, the in-camera sharpening settings are ignored — expect to do any sharpening during RAW file processing, or in image-editing software after processing.
In all instances, rely on the recommendations of your photo desk if you shoot for any news or photo organization. If the Photo Desk says that sharpening will be done at time of processing, we strongly suggest setting in-camera sharpening to “zero” unless testing by your organization leads to other instructions from your photo desk.
Suggested starting points for Unsharp Mask sharpening in the computer:
For shooters who anticipate making further sharpening adjustments in Adobe Photoshop™ or similar software programs, always bear in mind that ideal sharpening settings will be very much dependent upon subject matter, lighting, ISO setting used, and of course the intended type and size of final output. As a typical, initial starting point for sharpening using Photoshop’s Unsharp Mask command, you might want to consider the following:
High ISO images (no initial in-camera sharpening)
Low ISO images (no initial in-camera sharpening)
Amount — 250% Amount — 250% Radius — 0.3 pixels Radius — 0.3 pixels Threshold — 4 levels Threshold — 1 level
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