Image courtesy: portreti.lv.
One of the most annoying things on Sony SLT cameras is that you cannot use a wider than f/3.5 lens aperture when using the autofocus on video mode. But there is a workaround trick described at portreti.lv. Smart and easy solution!!!
Thanks Portreti!
37 Responses
Not bad if you like messing with expensive glass..
actually that picture is of a minolta 50mm f/1.7 which is about 60 dollars on ebay, sooooo… not as expensive as some lets say.
MA doesn’t stand for manual focus?
MA = Minolta Alpha (AF)
MF is Manual Focus
This sounds like a very bad idea. There is a mechanism on the front of the camera body that moves this aperture slider back and forth; who’s to say this won’t get damaged somehow? Also, I don’t feel comfortable pending this level on any of my good lenses, and any low cost el cheapo lenses aren’t going to be sharp wide-open anyway.
I don’t see the point of this. Here, let me start bending parts of my $2800 A99 and my $2k 24-70 lens to get 2/3 stop of light just for autofocusing in video mode.
NOT.
*pending the level = bending this lever (English translation):)
Are we sure both the lens and camera arent being damaged here? Because this will be wicked awesome!
Try affixing some scotch tape to the inner part of the lens. Works like a champ.
Ok redface time.
My biggest initial reaction was to “glue” or “bend”.
I have found if you take about an inch of scotch tape and fold it inside out (sticky side out) it will hold the lens wide open. This works without a hitch, and I have verified that it does in fact AF wide open. Pretty cool, and my apologies.
Of note – the “spring” may get worn out, and there’s no quick way to stop down either. The Sigma lenses so far have a much tighter spring than the Sony lenses so the tape trick might not work.
No way the spring can get worn out as the lens spends most of its life with the diaphragm fully opened wether mounted on the camera, or with it’s rear cap on.
This worked with the 24mm Zeiss. When I switched to the Sigma 50mm, the camera made a funny noise and read “camera error – Turn camera off and back on”.
Very cool but makes me very nervous.
The video mode in Sony Alpha opens wide up to F3.5 only? Any reason behind this phenomenon?
phase detection AF.
Could you elaborate please?
Is there a technical reason why the camera firmware is programmed to not go wider than F3.5?
Dunno. I’ve argued with people about this for years – my basic claim was if it can AF @ F/1.4 in stills mode, why not movie mode?
Probably to do with autofocus accuracy. The wider the aperture, the harder it is for phase detection to pick the exact focus point. So they force everyone to use a narrower aperture to make the movie mode AF look better.
As an aside, a lot of Sony/Minolta lenses use a spring inside to actuate the aperture. Rather than jamming/bending/taping the aperture lever open, a more elegant solution would be to open it up and remove the spring. Then simply refit the spring once one is done.
Might be more elegant, but you’ll still need something to hold it wide open. With the tape solution, I can take my fingernail and rip it out of there on the fly if I need to. Tape is cheap.
Hey Shawn! Impressive demonstration. Great workaround. I’d love to see a video of the actual tape being affixed to the lens. I’m terrified I’m going to do something wrong.
I was so excited I made a video with it and about it. I did credit the author of this site for the idea. I’m using scotch tape by the way; didn’t have to use glue or bend anything and it’s removable.
Thanks again for the great idea!
https://vimeo.com/53135961
The link shows no video…
works for me.
Yes sorry took a while for Vimeo to process it.
Works for me.
But in your clip AF takes a while. If you’d film people under this conditions it would become annoying waiting always a second or two before face is sharp…
This was shot with the Sony 50mm @ F/1.4. I wouldn’t even use the hack on this lens for a number of reasons; mostly because it’s too shallow AND not super sharp wide open.
Also keep in mind this was going from a subject about a foot away to the back of my basement wall, which is like another 25-30 feet away. How often do you shoot like this?
Sorry Sigma 50mm not Sony. Cannot edit.
If you are THAT concerned about selecting aperture, wouldn’t you simply go to manual focus? It isn’t hard.
AF is a nice feature for family videos etc., but I wouldn’t use it for a serious shoot.
This is pointless unless the AF can work in any other mode but exposure mode P.
What’s the point in having an aperture of F1.4 when it’s automatically going to adjust the shutter speed all the time? I’ve never used P mode but I assume it’s the same mode the camera automatically jumps into as soon as the Movie button is pressed in the stills modes.
If you can get the AF to work (not that I use AF in video at all) in Manual then I’d be interested in messing around with it but like someone said before only if it’s for P&S videos that you don’t actually care too much about.
You do see that big button that say AEL, right? You can set your shutter to whatever you want just by pointing the camera at light. So with the a99 that has Auto ISO in Manual mode, you have now have your lens wide open, shutter locked at 1/125 (for 60p) and either manually set ISO or let the camera automatically adjust it. What else is left that’s part of the exposure triangle?
Maybe this F3.5 limit in video for SLT/PDAF, like the ISO 1600 or ISO 3200 limit, is to not overheat ? This is the explanation for A77 from Paul Genge of Sony UK: “ISO is the name given to electronic Gain up. To generate higher sensitivity the sensor has increased voltage passed through it, this also increases the heat generated. Video recording keeps the sensor operating at a high temperature too. Therefore we limit the sensitivity to 1600 ISO equivalent. Aperture is limited to F3.5 or the maximum the lens can offer for the phase detection autofocus to still operate during recording.”
To stop down shutter speed, just use right ND filters!
Yes, of course, movie controls (and live histogram) like Panasonic GH series is much better and user friendly, but this is Sony, this is (only) fullframe camera with usable autofocus.
Now if only you could remove the damn clicking noise alpha lenses make when ever they autofocus during video…
You can, it’s called SSM and my 16-50mm is lovely… 😉
I know what you mean. My Sigma 16-50 HSM is actually quieter autofocusing (it sounds like a low, dull soft thud) whereas my Sigma 70-200 HSM has a more distracting (click, thunk sound). I think Sony should have taken a cue from Nikon and marketed something like the ME-1 which reduces the autofocus noise picked up during recording…By the way, with regard to the maximum aperature fix: I would recommend you use a twist tie for the bag on a loaf of bread. When I used to own an Eclair ACL, I would have to use this trick to adjust Canon lenses to my 16mm camera and someone on a forum recommended this trick and it worked like a charm.
Use external mic!
The problem I see with this method is that the camera is going to misadjust the exposure because it thinks the lens is set at 3.5 when it is really at a wider aperture (let’s say 1.4). If you are in a semi-well lit room where f3.5 would need say +30db gain, then f1.4 would need only 15db gain. But with this method, the camera thinks the lens is at f3.5 when it is wide open meaning the camera is miscalculating the proper exposure and overexposing. So you would get autofocus, but you would have to manually set the exposure by locking in the gain (I think +3db gain=+1/2 stop of exposure compensation).