Do you have focus?

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2 years 10 months ago - 2 years 10 months ago #3257 by WT admin
Do you have focus? was created by WT admin
I am a sharing this as I had recently had an issue with focus on a lens and I was advised to check the focus calibration myself.

My big (Hernia 600) lens is the sharpest thing I have ever owned, but when using a TC and shooting at distance (the reason I bought the lens) it just didn’t impress me. So I asked around on online forums and was told this is in fact very common and I should consider setting up all my long lens individually with each camera.

This was a bit of a surprise to me – you would expect if you spend $$$ for a lens and $$$ for a body from the same manufacturer then focus heaven should be guaranteed.

So I asked around and was advised of a piece of software called ReiKan Focal (although you can find online alternative manual non software solutions). Not cheap at 100$ but it would do the whole len's calculation “automatically”. As my eyes are not the best I plumped for the software.
I struggled for a while getting it to work with my mac and then decided to try with a PC and it worked first time. You have to control the setup and conditions but once its working – bingo.

My “hernia” (Nikon 600 ED) was spot on (0 and +1) with both my regular bodies – this was not a surprise as it produces the sharpest pictures I have ver taken. BUT when I put on a 1.4 teleconvertor the readings showed a +14 variation with focus – on both bodies. Focus was out.

I then decided to try my 300 PF bare. I had been suspecting I had somehow “knocked” this out of focus and was intending to send it in for maintenance as soon as I could get time to go to Nikon. I had recently taken a number of otter pictures with it and none had been in focus. A big disappointment. After passing the body/300PF combos through the software it was revealed that this lens was +8 and +9 out of focus bare on each body respectively.

To give these numbers some meaning – this means at distance it becomes harder and harder to achieve focus (you may have “focus” at say 6 meters but not at 18 meters) – 0 is perfect, 20 is you have no option but to send it back to the manufacturer. Not all bodies work with the ReiKan software or have in camera adjustment to fine tune focus but if you are questioning critical focus of your rig – it may be something you may want to consider.

The software will tell what adjustment settings to program into you camera AF system to correct the focus without having to go to the service center.

So I have learnt something – It’s not always the failure of the camera operator – the camera lens combo can be the cause of error as well.


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