FS700-LAEA2-Adap[ter-Spmu 70-400mm Autofocus lens...no Iris control?

S

Scott Ransom

Member
I recently set up a FS700 with the LAEA2 adapter and the Sony 70-400mm Auto Zoom. Great set up actually....but I am unable to get iris control when the lens is in autofocus mode. I can get it when in manual.....but not autofocus. Strange because the kit lens allows iris even in auto.

Anyone dealt with this?

SR
 
Scott Ransom said:
I recently set up a FS700 with the LAEA2 adapter and the Sony 70-400mm Auto Zoom. Great set up actually....but I am unable to get iris control when the lens is in autofocus mode. I can get it when in manual.....but not autofocus. Strange because the kit lens allows iris even in auto.

Anyone dealt with this?

SR
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With the laea2 adapter the aperture is fixed to 3.5 in auto focus mode
 
I've just got my LA-EA2 and I have some minolta af 2.8 zooms arriving today. I'm thinking of getting a minolta 70-210 beercan but it's f4. Just curious what happens if you try to use autofocus with it as it won't go to f3.5. Any ideas?
 
MBradshaw said:
I've just got my LA-EA2 and I have some minolta af 2.8 zooms arriving today. I'm thinking of getting a minolta 70-210 beercan but it's f4. Just curious what happens if you try to use autofocus with it as it won't go to f3.5. Any ideas?
Click to expand...

The aperture is fixed at wide open or F3.5 with the faster lens. Since minolta 70-210 is F4, the aperture will be set to F4 if you enable the AF. The OP lens was 70-400mm F4-F5.6, so obviously the AF still works fine even at F5.6 when the lens is fully zoomed.
 
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I've just got my lenses. One of them is a 17-25 2.8/4. When the lens is wide and the iris can therefore reach 3.5 autofocus works. As soon as you zoom in and the iris steps down the autofocus stops working. With the f4 lens it just doesn't autofocus at all.

Kind of what I expected really.
 
MBradshaw said:
I've just got my lenses. One of them is a 17-25 2.8/4. When the lens is wide and the iris can therefore reach 3.5 autofocus works. As soon as you zoom in and the iris steps down the autofocus stops working. With the f4 lens it just doesn't autofocus at all.

Kind of what I expected really.
Click to expand...

If this is really how it works - BUMMER !
 
It sounds like you have some experience with this lens and adapter combination? I am scouring the tech world for answers....so any help you can give appreciated. Is it the case that when in autofocus mode.....the Sony 70-400 autofocus lens will not allow manual control of iris? If not.....is it the case that everything shot with the lens in AF has got to be shot at f4? Please don't tell me that. WTF!

Anyway....please get back to me with any help at all. Or call me....Scott at 970 209 3139.
 
Hi Scott, if the lens is capable of f3.5 then autofocus will lock the iris to 3.5 and that's it. I don't have a 70-400 but my minolta af beercan is f4 so autofocus isn't possible. The autofocus works well but as you are stuck at 3.5 you will have to adjust exposure with variable nd's and gain.
 
Thanks M. Good final advice on the system. Have ordered Variable ND and will just have to get used to it I guess. Either that or go manual which is what I have always done. Thanks for the note.
 
MBradshaw said:
I don't have a 70-400 but my minolta af beercan is f4 so autofocus isn't possible. The autofocus works well but as you are stuck at 3.5 you will have to adjust exposure with variable nd's and gain.
Click to expand...

This is incorrect.

If your lens is capable of f3.5 or larger, then the camera will fix the aperture at f3.5 if you activate AF.

HOWEVER, if your lens is not capable of f3.5, you can still use AF at the wide-open aperture.
 
ordered my 70 400 and looking to see if i would still have auto focus with 2x or the 1.4 teleconverter ? someone tried this yet? would be great to know before i bought it.
 
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