"shutter priority mode"

[Mark Howells]

Hi. Just used my Panasonic hc-v750 camcorder for the first time to record my daughter's sports day. I want the shutter speed fixed at 1/50 for normal motion (UK). I therefore used manual mode and set shutter to 1/50. When I have tested this inside, the iris changes automatically to give the correct exposure, which is what I want, an effective shutter priority mode. However, outside the iris maxed out at f8 meaning that the footage was consistently over exposed. It needed to close down more up to f16 which I know it is capable of.

I've looked in the manual and searched on the internet but I can't find an answer. Do you think this is correct that in manual mode 1/50 shutter the iris will not close down lower than f8 automatically or have I got a faulty product. I can obviously also adjust the iris below f8 to f16 but if I need to pan the camera to follow my children the exposure would be fixed which is not what I want.

If anybody has a similar camcorder and can advise that would be superb. This just seems so strange!

[Adam Gold]

Sony camcorders often have an AT IRIS LIMIT setting to prevent the iris from stopping down too far when in auto mode. Perhaps the Panny has something similar.

[Daniel Epstein]

Some camcorders don't have good results with Iris's closed farther than F8 anyway. You might need an ND for the lens. or some way to set the sensitivity lower if possible. I would check the manual or ask Panasonic what they recommend.

[Mark Howells]

Thanks guys. I must admit I've never heard of limiting the IRIS. I would have thought that if you wanted to shoot at high f numbers with its associated distortions it should be your choice, especially in a consumer camcorder. It shouldn't be dictated by the manufacturer. I couldn't find any mention of it in the manual so I have sent an e-mail to Panasonic. In fact I started a live chat with a Panasonic representative but as soon as I asked my question, I was disconnected. Funny that.
I guess I will have to use my variable ND filter to bring the exposure down below f8.
Seems a bit of a faff for home videos.

[Daniel Epstein]

Mark,
In order to save money on these camcorders the manufacturer makes all sorts of choices we might not expect. Also depending on the size of the sensor it is very hard to make lenses with irises which work at the Higher F numbers. Common for small HD sensors with lenses to have trouble above F8.

[Dave Blackhurst]

What is the minimum aperture on that lens? If it happens to be f/8... then there's your limit.

This is the tradeoff sometimes for the mythical beast of "lo-light", the system may then not be able to reduce light coming in enough for "HIGH light" conditions and ideal shutter/aperture combos/settings. Thus ND's to reduce the light coming in to compensate.

[Mark Howells]

The minimum aperture is f16. If I point the camera at a cloud in the sky for example, using “shutter priority” of 1/50, I would expect the camcorder to close down the iris as much as possible but it defaults to f8. Obviously this results in a blown out sky. I can then manually adjust the iris down to f16 to give better exposure but then I can’t move the camera without having to correct the exposure by adjusting the iris again. This is impractical for following the kids on a sunny day and a sunny day will typically need above f11.
It just doesn’t seem right. Of course I can use a ND filter to bring the iris down below f8 and then let the camcorder control the iris in ”shutter priority” mode but this surely shouldn’t be necessary for a consumer camcorder. I’ve had a number of Panasonic and canon camcorders in the past and none have shown this characteristic.