Dedicated video lenses usually feature stepless aperture to allow for smooth adjustment of exposure. Most still photography lenses, in contrast, feature stepped aperture adjustment. This article demonstrates how to "de-click" Canon FD lenses to get stepless aperture.

Before you continue, note that

1. De-clicking is easy. All you need to do is to unscrew the rear and take out one or two things.
2. The process will not introduce dust into your lens---the optical assembly is sealed in one piece inside the lens.
3. There is a "cheat" that gives you continuous aperture adjustment without the hassle of opening up the lens. All you need to do is set your lens to the smallest aperture, then turn the ring on the FD adapter. The downside of this cheat is you do not have any indication of which f-stop you are at.

With that in mind, if you still believe de-clicking is useful---and I personally do find that being the case---here is a quick demonstration on how to do so.

1. Take apart the lens from the rear and remove parts that cause un-smooth movement

2. Remove the piston

If instead your FD lens locks with a rotating metal ring, you will need to remove the two ball bearings inside the aperture ring.

3. Removing the spring holding the aperture selector

4. Linking the aperture ring to the aperture diaphragm

If your FD lens locks with a rotating metal ring, you will be lopping around the coupling fork instead:

5. Re-assemble the lens. It's done!

I love to see a better video auto focus system. DFD has already removed the first wrong direction start of the focus pull, but I like to address the second wrong direction autofocus pull, the "focus confirmation" rack at the end of the auto focus pull.

I'm not an engineer but I like to understand what is happening what, how, where, when and why.

At this moment the Auto Focus system for video looks the same as for stills. And for stills it works fast and well, accept in continuous high when it has a hard time keeping up with fast action. For video (akin to a very high number of stills) the AF is way to slow, and the focus confirmation pull is very distracting and jarring.

If DFD is able to measure the blur amount, and therefore can measure how far the subject is, the I think a reprogramming of the focus system can help to get rid of that jarring focus confirmation refocus.

I can think of this focusing system:

Focus pull situation:

1) DFD measures the amount of blurr, 2) compares it to the current focus distance, 3) estimates subject distance, 4) smoothly starts racking focus, 5) measures amount of blur half way racking focus, 6) checks the blur shift amount of the first and second measurement, outputs second focus target distance, 7) at the last part of the focus rack the focus speed eases off to arrive at the second estimated focus distance.

Continuous AF situations:

1) DFD measures the amount of blurr, 2) compares it to the current focus distance, 3) estimates subject distance, 4) smoothly starts racking focus, 5) measures amount of blur half way racking focus, 6) checks the blur shift amount and compares it to the first measurement, calculates subject movement, 7) rack focus to second focus target distance, 8) checks the blur shift amount and compares it to the previous measurement, calculates subject movement, 9) repeat 7 and 8 until no blur.

10) If subject leaves the frame maintain the current focus distance for x time before starting with 1 on the new subject in the assigned focus area.

Maybe DFD blur measurements are hard & slow, so having measurements while the camera is auto racking focus is harder to do, but I prefer a slower focus much over racking past the focus and racking back in video.

As a compromise DFD could be used to make a 1 time focus distance estimate, the focus racks smoothly (s curve) to the estimated distance, and stops (without racking past the estimate focus distance AND racking back). This would be good enough for a G85, and the more processing heavy higher DFD sample rate for the high end GH5. I must admit this all hinges on DFD accuracy in measuring the blur and estimating the subject distance.

What do you people think? Love to learn how the current contrast and DFD actually works. Love to hear your suggestions of how to improve AF.

I, living in Norway, can only record for 29min 59sec. (This limit is an EU law has this restriction as it is a still picture camera and not a motion picture camera. Different taxes).