help- sigma 105os macro hood/extender?

[scott199]

Posted this in the equipment thread, but thought it might be better here

I have the sigma 105 os macro I got 2 hoods, well 1hood and a extension, now it says to use the hood on FF and extension on dx.

Seems sigma went to a lot of trouble to add/give this out.

So is it really needed and should I be using the extension ?

I tend to use the hood for protection anyway.

 

[MWHCVT]

Well are you using the lens on Full Frame or a Crop body? know that would allow us to answer the question

 

[StewartR]

The main purpose of a hood is to prevent unwanted stray light from getting into the picture. So ideally the hood would be as deep as possible without intruding into the picture. That's why hoods for wide angle lenses are shallower, and that's why some hoods are 'petal' shaped. OK?

Now what Sigma have realised is that if you use a lens on a crop sensor camera you have a narrower field of view, and therefore you can use a deeper hood before it intrudes into the picture. So that's why they make the two-piece hood. (It's not just the macro lens by the way; they do it for other lenses such as the latest version of the 50-500.)

So *if* you use a full frame camera then you must only use one part of the hood. But *if* you're using the lens on a crop sensor camera and *if* you're concerned about getting the maximum possible protection from stray light (eg shooting almost directly into the sun) then you should use both parts of the hood. If stray light isn't an issue and you're mainly using the hood for physical protection of the front element, then use whatever is most convenient or practical depending on the circumstances. And when shooting macro, you may well want to remove the hood altogether because the front of the hood will be very close to your subject.