Hot swap lenses?

[Derek Reich]

Is it okay to hot swap lenses with a metabones adapter (either the MKIV or Speedbooster)? I did that last week... took off my Canon 24-70 f2.8 w/ Speedbooster all at once. I didn't notice if it was doing this beforehand or not because I just got the camera, but now when I do a snap zoom I notice a 'flashing' in aperture. It's like a flashbulb going off... the aperture seems to be opening all the way then returning to where previously set. Is this normal? I don't need to use the snap zooms, but it's disconcerting to see when changing framing.

[Dave Sperling]

I'd recommend against hot swapping with the Metabones. Better to turn camera off/on. On occasions when I've forgotten the adapter may not connect properly with lens.

However, when using non-electronic lens adapters (Nikon, Leica) I've had no issues with camera staying on during a fast lens swap.

On a separate issue, have occasionally had issues with iris variations when zooming -- it may have been from the twisting of the lens messing up the electronic contacts with lens or adapter. Had nothing to do with hot swapping.

[Cliff Totten]

That's a funny question that I have always asked myself. It's probably perfectly fine to do but I always get freaked out by it. I dont know why, it just feels "akward" and makes me feel very "uneasy" seeing a body powered on with no lens attatched.

I don't do it. But that's just me.

CT

[Derek Reich]

I don't like to either, but sometimes you have no choice. My Canon C300s had a 'lens exchange' button which shut down the sensor and power to the lens, w/o shutting the whole camera down. It was very quick and felt safe. I'm a bit disturbed by the iris flashing on the metabones speed booster... has anyone else seen this?

[Jeremy Cole]

Yep, I hot swap lenses with and without Metabones adapters, though I am a Sony and Nikon mount guy so not really an issue with Metabobes electronics.

[Piotr Wozniacki]

Originally Posted by Dave Sperling

On a separate issue, have occasionally had issues with iris variations when zooming -- it may have been from the twisting of the lens messing up the electronic contacts with lens or adapter. Had nothing to do with hot swapping.

The above "side note" statement caught my attention, Dave. What do you exactly mean by "iris variations when zooming"? Because what I've noticed with my 2 Canon lenses on Speed Booster and FS7 is quite noticeable ramping of lens brightness when zooming in fully; both these lenses (the 16-35mm and 24-70mm) are supposed to have constant aperture, so it might suggest it's the Speed Booster tat causes the ramping...

Has anyone noticed it? And BTW - apart from light loss at tele - I find my Speed Booster is not delivering to the "doubling the max aperture of the lens" marketing blah blah, unfortunately :( Sure it does make my Canons (both F4) a bit brighter, but - even though reported to the camera as F2.8 - I personally rate them as F3.5 max... What's other users experience in this regard?

Piotr

[Derek Reich]

Piotr,
when you say 'ramping', does it very quickly ramp all the way open, then close just as quickly back down to the set aperture? Mine does that... it's like a flash going off when you are looking through the vf. And it can happen multiple times in the zoom, depending on the speed of the zoom.

[Dave Sperling]

Piotr -

No, I wasn't referring to exposure 'ramping'

It was a fast but extremely noticeable change in iris - so if I were shooting at 4.5 and the lens was a 2,8, as I was zooming the iris would suddenly open fully and then stop back down to where it should be.

I'm assuming that what was happening was that the twisting force of manually zooming the lens was momentarily shifting the ways the lens was sitting and making electronic contact with the adapter (or the adapter's electronic contacts with the body - since we're talking two contact sets here) and that was creating an electronic glitch.

In terms of lens exposure ramping with a speed booster --
I tend to shoot with Nikon lenses more than with Canons, so I won't comment on the specifics of the Canon lenses. But, I do find that most still zoom lenses I have do experience some kind of exposure variation when changing focal length, even the ones that are theoretically 2.8 all the time. My Nikon 28-70 2.8 seems to vary about 1/4 of a stop.

One other thing to remember is that with the speedbooster you are using the full field of view of the lens, not just the 'center sweet spot' you would be using with a non-speedbooster adapter. The wide lenses in particular tend to experience light falloff towards the corners of the frame, and this usually varies when zooming.

Do a quick test on an evenly lit gray (white) wall - (evenly lit but only exposed down around 60% or 70%. Put the camera output through a waveform (or check it in post.) Or if no waveform is around use your zebras. See what happens to the exposure when you zoom. I think you'll agree with what I've seen here.

[Derek Reich]

That sounds exactly like what I have been experiencing too. I'll have to sit down and compare the speedbooster to the MKIV and another adapter I have and see if they're all consistent, or if one is more prone to doing this than another.

[Piotr Wozniacki]

Originally Posted by Derek Reich

Piotr,
when you say 'ramping', does it very quickly ramp all the way open, then close just as quickly back down to the set aperture? Mine does that... it's like a flash going off when you are looking through the vf. And it can happen multiple times in the zoom, depending on the speed of the zoom.

No Derek - I never get the aperture "flashes"; what I mean is just an observation that my Canon lenses which are constant aperture through their entire zoom range, lose considerable amount of light when on the Speed Booster - so they're not as bright at tele as they're at wide. The most "classical" definition of aperture ramping...

Piotr

[Derek Reich]

So here is an update:
I was on a shoot a few days ago, and a little over an hour into the interview, I started getting these 'flashes' in exposure without touching a thing. They just started randomly. At first I thought it was a flash of lightning outside or something, but then it did it a few more times. I had to stop the interview (I was seeing it on the output monitor, so I knew it was getting recorded) and quickly put my MK IV on, hoping that would solve the problem. We were able to finish the interview without issue, but I was pretty sure I must have a defective Speed Booster or something.

Then another one of our NY crew asked if I hit the 'little button' on the adapter prior to booting the camera up. "what button?" was my reply. He showed me the little button on both adapters and said you need to hold these down when changing lenses or powering the camera up... at least initially until the adapter recognizes the lens. I was skeptical, but we did that, and the flashes stopped... at least for the moment.
So, what is the deal with the little buttons, and why does Metabones not make this more clear? Or is it possible I still have a defective adapter? I don't see too much on here from other posts experiencing this level of issue. Very curious.....

[Alfred Okocha]

Little button? I hot swap occasionally and never had a problem. Never pressed any button though...