Petal Lens Hoods

[Steve52]

Just a query really.
When holding a camera in the horizontal position, should the longest part of a petal lens hood be at the top, side, or doesn't it make any difference?
I would have thought at the side, as if a flash gun is attached, there is more chance of a shadow being created if the longest part is at the top.
The instructions that came with my Sigma lens, show the longest part at the top.

[Roger_Provins]

Take the lens hood off when using a flash on the camera. The longest parts of a petal lens hood should always align with the widest part of the sensor frame. It's probably impossible to put it on wrongly anyway.

[Wheelu]

It should be impossible to mount a bayonet fitting hood the wrong way around, but many older or third party hoods are screw fitting, or clamp to the screw thread, so you do need to know what you are doing.

If you think about it, the lens produces a circular image and a rectangular sensor or negative will approach the limits of that circle more closely at the shorter sides. Therefore to avoid vignetting you need to use the shorter petals adjacent to the shorter length of the sensor/film. I.e. in landscape format the larger petals go at the top and bottom.

[Steve52]

Thanks guys. Just tried, and it will only go on one way. Will try and remember to take it off when I use the flash.

[jchrisc]

Thanks guys. Just tried, and it will only go on one way.

Although they will only go on one way, there is often enough "slack" to allow them to be partially rotated and still remain in place. I have ruined some images by failing to notice a partially rotated petal lens hood. Take care . . . [img]/forums/images/graemlins/tongue.gif[/img]

[parisian]

Take the lens hood off when using a flash on the camera.

??????
AFAIK that may apply to close range work with a built in flash but otherwise no.

[velocette]

The Sigma one on my 17-70 certainly 'creeps' if I don't keep an eye on it. I've had to crop a number of masterpieces where the damned this has moved round obscuring the corners. Could be of course that it's a built in compositional aid by Sigma.

[beejaybee]

The Sigma one on my 17-70 certainly 'creeps' if I don't keep an eye on it.

Mine doesn't .... OTOH it's pretty useless as a lens hood, it doesn't give much shade even when the lens is zoomed right out, and towards the tele end it gives no useful shade at all. A common failing with zoom lenses. If the thing didn't fit into my bag with the lood attached - thereby giving some mechanical protection - I'd solve the "problem" by removing it altogether.

[Roger_Provins]

Take the lens hood off when using a flash on the camera.

??????
AFAIK that may apply to close range work with a built in flash but otherwise no.

I think Steve is using a Sony a350 which has a particularly low pop-up flash and it's quite surprising just how much a lens hood will shade the flash output.

[Steve52]

I think Steve is using a Sony A350

Yes. I am (and an A100). However, this lens was bought primarily for my band work, so I doubt I will use it with a flash.

[fabs]

Take the lens hood off when using a flash on the camera.

??????
AFAIK that may apply to close range work with a built in flash but otherwise no.

I think Steve is using a Sony a350 which has a particularly low pop-up flash and it's quite surprising just how much a lens hood will shade the flash output.

But I think Steve is talking about a flashgun here?