1200mm: Digital Teleconverter

Started 8 months ago | Discussions thread
JimH123 Senior Member • Posts: 2,744
Re: Not Interpolation Re: 1200mm: Digital Teleconverter

OutsideTheMatrix wrote:

JakeJY wrote:

Eric Nepean wrote:

OutsideTheMatrix wrote:

But it is only throwing away data that is outside the area of interest and which may not be of any interest to the photographer. I shoot RAW+JPG now (only the JPG file part shows the DTC), why doesn't Oly make the x2 DTC filter available in Work Space so people can apply it to their RAWs? It should work the same way! Also, I sometimes use M size 5 MP for x2 DTC to get a nearly non interpolated result (5 MP vs 4 MP not much different) to get a much faster burst shooting rate, especially with the fully electronic shutter on my EM10Mk2.

But when using x2 DTC at the full 16 MP I do see more crater detail on the moon than I see without the DTC.

The RAW image contains the RGB values of every pixel. This is all the detail that was captured. Some of it is already interpolated, because every pixel is either Red or Green or Blue, and the other two colors are interpolated from adjacent pixels.

RAW contains the non-interpolated results as far as I know. It basically gives the value for each pixel and then during RAW processing is when you actually interpolate/demosaic and get the RGB values. The only pixels that may be already interpolated in the RAW file are the PDAF pixels and also pixel mapping (to fix dead or stuck pixels).

No more detail than this can be extracted from the sensor.

Example:

You have a G9, which has a 20MP sensor and no lowpass filter. You have mounted a good quality 25mm lens, and it is focussed on a wall 41 feet away.

The vertical field of view is 21 feet 3 inches (6.5m), and the sensor has 3872 pixels in the vertical direction.

Each pixel covers an area 1/16 x 1/16 inch (1.67mm x 1.67mm)

Pasted to the wall is a sheet of paper with two lines of text, printed 1/16th of an inch tall:

Donald Trump will win the USA 2020 election

Donald Trump will lose the USA 2020 election

The camera takes an image.

With 1 pixel per letter height, there is no interpolation software in the world that will bring the information in these lines back. You could just as well have written

Outside the Matrix will be the next US president

However if you add in 4x optical teleconvertor, there will be 4 pixels per per line of text, and 3-4 pixels per character, you should be able to read that.

Building a 2X or 4X Digtial TC for a RAW image isn't possible.

I don't think he is talking about necessarily doing the same as digital zoom, but rather just to do a cropped RAW. That should be theoretically possible. Camera only needs to read a smaller portion and write to the RAW file with that crop. Fuji uses a mode similar to that with a 1.25x crop to get faster burst speeds.

Yes thats why I'm thinking of using M size 5 MP and combining that with x2 DTC. Would the RAW still be 16 MP? If that's the case this might only be useful for JPG only mode for faster burst speeds as I could do M F 5 MP JPG and perhaps get over spec in fps with the electronic shutter.

There may only be one way to pull the sensor data from the sensor and selecting a smaller JPG resolution may still have to pull all the data from the sensor into the camera.  But once that data is loaded into internal camera memory, then perhaps the processing of the file can be faster and the writing of it to the SD card can be faster.

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