Originally posted by philodragon I'm new to buying lens hoods, as well as being new as a Pentax owner, and would like to know if all lens hoods will work on a lens as long as they state the same size as the lens (i.e. - 49mm). Are lens hoods standard across the manufacturers or do they differ in some way even if they are say 49mm?
I'm looking to buy some hoods on eBay but some do not specifically say Pentax on them. I'm wondering if they will still work for my lenses, provided that I buy the one that corresponds to my lens.
There are a lot of factors for a lens hood, but the three critical are as follows:
-filter diameter. Obviously, of it can't screw onto the front off the lens it won't work (same for bayonet type hoods,mr hey must be compatible with your lens)
- hood depth. Deep hoods offer more protection for flare and also boost contrast by reducing the light outside the lens field of view from entering the lens, this light must be absorbed internally in baffles and can lead to reduced contrast as well.
-hood diameter is also important, a hood that is significantly larger diameter needs to be proportionally longer on any lens to offer the same protection
For me, I like hoods that are just large enough to be turned over and fit over the lens barrel for storage in my bag.
There is a file, which I uploaded some time back called hoodcalc. It is a spreadsheet that can calculate the optimum hood length for any known diameter loos, and for any lens focal length/sensor combination