Learning a new Lens
Not all lenses are going to be compatible. For example, my Sigma 16mm lens didn't work initially. Luckily, Sigma had since released a software update that let me add it. So, if at first you don't succeed... try upgrading the firmware :)
(you can skip this if you want - users of more recent cameras that had to be switched from libusbk to MTP may not be interested in flip-flopping just to get the Remote program to run)
- First, load up the "Sony Imaging Edge - Remote" tool on your PC - I'm not sure if it supports any OS other than Windows
- Connect your camera
- In the panel on the right is a section that allows control of focus
- Open it up if necessary by clicking the small ">" to the left of the word "Focus"
- Make sure focus mode is set to MF
- Try clicking on the various
<<<,<<,<,>,>>,>>>buttons and see if the focus changes on your camera
If focus moved, then you're most probably going to have success with the following instructions. If it didn't, then see if you can upgrade the firmware on the lens and try again.
This is a temporary page explaining how to use the cobbled-together "lets learn your lens" tool.
The tool is a text-based application that goes through the steps of learning the number of steps your lens needs to get from one end of its focus to the other.
Each lens seems to have a different number of steps, and we need to know them as accurately as possible to drive focus properly from a tool like APT or NINA.
Sony allow for seven different step sizes on the USB interface the ASCOM driver uses - although the Imaging Edge Remote app only supports 3 of them.
| Step Size ID | How Big | Imaging Edge Remote Uses? |
|---|---|---|
| 1 | Smallest possible | Yes |
| 2 | Bigger | - |
| 3 | Bigger Still | Yes |
| 4 | Even Bigger | - |
| 5 | Large | - |
| 6 | Even Larger | - |
| 7 | Huge | Yes |
On my Sony kit lens, there is exactly 1 step at size 7 from one end of the focus to the other, and around 260 at size 1. On my Sigma 16mm lens, there are nearly 4 steps at size 7 and over 1,000 at size 1.
Note how I said "nearly 4 steps"... what? When the focus moves, it moves in equal steps from one end to the other. These steps are not guaranteed to be split evenly. So in my case, move #3 got the focus most of the way, but I needed to move it one more time. Visually, this was a smaller step, and if the camera display had been able to, it would have shown that the lens moved past the end of the "bar". I had to guess that it was about 0.9 of a move.
It is very important to get a good guess for the bigger step sizes.
ENSURE YOU HAVE MANUAL FOCUS SET
First, the tool will try to move the focus all the way to INFINITE. Watch the camera screen and ensure you see the bar move all the way to the right.
Next, the tool will move one step to the left, using the biggest step size (7). You need to watch the camera screen to see how far it moves. This will help you guessing estimating the size of the last move. The tool will ask "Are we there yet?", if the bar has reached the hard-stop at the left, answer Y, else press any other key. This will repeat until you're at the far left.
At this point, the tool will say something like "I moved it X steps, how many steps would you like to set?". This is where your estimation skills come in - did it really move 4 steps, or was it actually more like 3.5? Enter this number.
Now, it'll move all the way back to INFINITE, and start learning the next smallest step size. It'll try to make your life a little easier at this point. To date, all lenses have had a fairly similar ratio between step sizes - this has always been between 2:1 and 2.7:1 - so the tool will automatically move a number of steps for you, getting the focus position close-ish to the left. Your job is to take those final steps, again, trying to estimate whether that last step is full-size, or smaller.
This is repeated for each step size down to 1.
As you get past the first 2 or 3 loops it will probably be hard to tell if it was a partial step - that's fine, just go with the suggested number.
When you get down to sizes 1 and 2 (or possibly higher) it will be come increasingly difficult to see the focus-bar move on the screen. For example, on my 16mm Sigma, size 1 would move the bar about a pixel every 10-15 steps... so you may need to get your glasses on and start counting steps to get a good idea. This will be a best-guess.
At the end, the tool will print out a list of step-sizes and the number of steps you entered... Please take a screen-shot, or copy the numbers - I need them!.
Send me an email @ retrodotkiwi@gmail.com with the following info:
- Lens Manufacturer
- Lens Model number (if known)
- Lens Name (this is either from the lens or the manufacturer website -- or the box :) )
- The list of seven number pairs
If you put the numbers into a spreadsheet and graph them you should get something like this:
If you switch the scale to Log, you should get a straight line:
If you add an exponential trend-line, it should be a straight line, passing through most of the points. It will probably miss the biggest steps by a little - I don't think the steps are necessarily ideal.
