Vignetting

[Wayne Els]

Researching flashes the YN 468II is described as unsuitable for FF cameras as it may cause vignetting in the corners. I'm assuming this is to do with the FF sensor but can't really figure out why it would only effect FF. Does anyone know anything about this issue?
Also would it only really prevalent at wider angles and be partially solved with either a diffuser fitted or shooting through an umbrella or softbox?
Thanks in advance for any help.

[colin C]

Re: Vignetting

I think you have worked through the logic and have the answer ........ it's down to the wideangle lenses. Either of your solutions would solve it, but the easiest may be a Stofen diffuser.

[S_J_P]

Vignetting

That's interesting, I'd not read that!

Flash coverage can be a thorny issue, Canon's speedlites can sense whether you have a FF or crop sensor and adapt their zoom setting to compensate, they also have the option to elect to have better flash coverage or increased flash-power by limiting coverage through the use f custom function settings. I'm sure that other companies may boost their flash guide numbers by restricting the flash coverage to a degree, perhaps even to the point of quoting crop sensor flash guide-numbers! Third party 'guns may also not be able to take account of crop sensors lessor field of view (e.g. 50mm lens on a crop camera only needs the flash zoomed to 80mm to provide full coverage). Perhaps this is what the the vignetting comment was referring to?

Whatever the cause of the vignetting you have to consider how much of an impact it will have. Flash will only ever illuminate a single distance correctly, and that usually means a single subject which won't occupy the entire field of view and as such a restricted flash coverage (either intentionally by manually zooming the flash head or automatically) isn't detrimental to the final image. In fact limited coverage can be an advantage, avoiding over illuminating close by objects which aren't the focal point of the image, and boosting power and effective range. Think of the flash as being a spotlight illuminating a single performer.

[Wayne Els]

Re: Vignetting

Cheers Colin.

[Wayne Els]

Re: Vignetting

S_J_P, Thanks too. I was just thinking that! If I'm taking a pic of an object, be it a person or a whatever say an object inside a scene (more light painting) it's kind of irrelevant as I'm not trying to evenly illuminate the entire field anyway. Creatively it could be a bonus that the rest of the image isn't lit, almost like a dof effect with light. Ponders some more...

[S_J_P]

Vignetting

Zooming the flash to create a pool of light can really help pick-out your selected subject. Here's an image I took last weekend on a very dull and overcast afternoon, lit by a flash zoomed in (to around 80mm I think) on an off camera cord and held high to the left. It's placement and zoom has prevented the surrounding foliage from blowing out or detracting from the main subject.

Let's try that again, I couldn't work out how to post an image from the iPad!

8380943089_71d10605c9_b.jpg
EOS 60D / 600EX-RT Flash
1/13th @ f/4, ISO400
17-40mm @ 17mm