This is from Schneider Optics' website (parent company of B+W) regarding their screw in metal hood for wide angle lenses with a 77mm filter thread. They list that this can be used on wide-angle lenses with up to 70° image angle. Now is the 70° angle for 35mm format (24x36mm film frame) lenses - and would that specification be different for a medium format wide-angle lenses?
The Pentax 645 A 35mm f/3.5 has an angle of view of 90°, so does that indicate that this B+W lens hood will cause vignetting? Can anyone out there help this physics challenged photographer with this answer?
The B+W #920 wide-angle metal lens hood is made of black-anodized aluminum with light-absorbing flat black ribs on the inside and protects against contrast-reducing, uncontrolled, stray light. It is designed for wide-angle (zoom) lenses with angles of view up to 70° wide (approx. 28mm in 35mm format).
- the Pentax 645 A 35mm f/3.5 is equivalent to a 21mm lens in the 35mm format.
I use a fair number of S&W hoods and step rings: they come in pretty much all shapes and sizes: as a sort of generic brand, they may not always be sold by name on Ebay, but I can name one dealer who has a lot of them. I think they're quite sufficient for a lot of things, (round hard plastic is usually my preference, with metal a close second) and hold up just as well as you may need, to my experience.
What I use with my Mamiya is just one of the big non-foldey rubber Mamiya ones: since it works with both of the lenses I have for it, I actually swap it between them when I change lenses, (cause it's beeeg: also, in my case, the hood wears a step-down ring to the filter size I use, so this keeps it all fairly small. (the Mamiya rides lens-up in a bag, so the hood's size isn't a big issue) You could possibly replicate my scheme with one of those Hama-style three-position hoods, which seem to be nice enough, and conveniently-threaded. )
There's a specific Ebay seller I have gotten a lot of that S&W stuff from, I forget if it's OK to mention someone in particular. But most of his stuff is nice as well as reasonably-priced. The nice thing is he usually has all that stuff in whatever depth and size you may need.
(Oh, and on this: )
"Now is the 70° angle for 35mm format (24x36mm film frame) lenses - and would that specification be different for a medium format wide-angle lenses?"
Nope, angle of view is angle of view. By format and focal length, these will change relatively-speaking, but as long as you know the angle of view of the lens and film size you want to put it on, 70 degrees is seventy degrees.
Last edited by Ratmagiclady; 11-07-2009 at 07:06 PM.
I have a rigid, rubber (I think that it's rectangular) Mamiya lens hood for a 45mm 645 lens;the front of the lens is 77mm. This hood slides on, over the outer edge of the lens. Don't know what size your lens is.
Hi Peter, thanks for the reply. Unfortunately KEH doesn't have a photo of the item available. I'm hoping someone who has tried a hood, and knows it works, will reply.
B+W makes lens hoods in addition to their filters. They make rubber and metal screw in hoods. I am trying to find out if one of their screw in hoods would work with my 645 A 35mm f/3.5 wide angle.
My 645 A 55mm f/2.8 came with a generic, metal screw in lens hoods that works really well. I should have thought of that when I was looking for a hood for my new 645 A 35mm f/3.5
I'll let you know if I find something suitable.
Thanks Yuri. It looks as though we're in the same boat. When I find something that works, I'll post as well. Then others looking for hoods for these lenses will have an easier time.
This is from Schneider Optics' website (parent company of B+W) regarding their screw in metal hood for wide angle lenses with a 77mm filter thread. They list that this can be used on wide-angle lenses with up to 70° image angle.
...
- the Pentax 645 A 35mm f/3.5 is equivalent to a 21mm lens in the 35mm format.
Thanks.
Yuri
Given that 70° is less than the 90° angle of view for the 35/3.5, I'm sure it won't work. And at $47.50 it would be an expensive test.
B&H has a number of hoods for medium format available (Lens Hoods), even for Pentax 645, but none for the wide angles.
Adorama has a better selection of hoods to choose from, but it's still a hit or miss situation. Lens Hoods
I use a fair number of S&W hoods and step rings: they come in pretty much all shapes and sizes: as a sort of generic brand, they may not always be sold by name on Ebay, but I can name one dealer who has a lot of them. I think they're quite sufficient for a lot of things, (round hard plastic is usually my preference, with metal a close second) and hold up just as well as you may need, to my experience.
What I use with my Mamiya is just one of the big non-foldey rubber Mamiya ones: since it works with both of the lenses I have for it, I actually swap it between them when I change lenses, (cause it's beeeg: also, in my case, the hood wears a step-down ring to the filter size I use, so this keeps it all fairly small. (the Mamiya rides lens-up in a bag, so the hood's size isn't a big issue) You could possibly replicate my scheme with one of those Hama-style three-position hoods, which seem to be nice enough, and conveniently-threaded. )
There's a specific Ebay seller I have gotten a lot of that S&W stuff from, I forget if it's OK to mention someone in particular. But most of his stuff is nice as well as reasonably-priced. The nice thing is he usually has all that stuff in whatever depth and size you may need.
(Oh, and on this: )
"Now is the 70° angle for 35mm format (24x36mm film frame) lenses - and would that specification be different for a medium format wide-angle lenses?"
Nope, angle of view is angle of view. By format and focal length, these will change relatively-speaking, but as long as you know the angle of view of the lens and film size you want to put it on, 70 degrees is seventy degrees.
Thanks for that. I'll look for S&W stuff and see what might work.
This is a picture of the Mamiya lens hood for the 45mm 645 lens;77mm front. You can see how the back is set up to slide/push on over the outside of the lens.
For my FA 45mm F2.8 I use a 67mm WA rubber screw-in I got years back from Adorama. It is cheap but seems to do the trick for now. Not sure for how long thou since the rubber starts separating from the metal ring.
This is a picture of the Mamiya lens hood for the 45mm 645 lens;77mm front. You can see how the back is set up to slide/push on over the outside of the lens.
I think that the Mamiya 45mm lens has a 76 degree angle of view.
Peter, thanks for that link. That looks like a functional hood, however the 35/3.5, which has the 77mm filter size has a 90° field of view. So, while it may fit physically, it will most likely cause vignetting. I wish this were easier. Thanks for the effort though.
For my FA 45mm F2.8 I use a 67mm WA rubber screw-in I got years back from Adorama. It is cheap but seems to do the trick for now. Not sure for how long thou since the rubber starts separating from the metal ring.
Arg! Yes, my mistake. Bayonet on FA lenses. And I should know since I have a couple right here!
Robin, you're partly right! Looking at my FA 645 45/2.8, it has no bayonet mount for the hood. The original hood must be screw a mount. Sorry about the confusion.
just looked up my 'early FA lens manual' and it states the following lens hoods for the FA 45mm f/2.8
Hood Type: PHRBC67mm
and for the FA 75mm f/2.8
Hood Type: RH-A 58mm
I don't have a late enough manual for the 645 A series lenses that includes the 35mm f/3.5... still searching
Yes, I've found the same info. The those hoods can be found on occasion at KEH. Unfortunately, they're both rubber, which have a tendency to warp and look ugly (not that I'm any great judge of beauty).
So, I guess I'll have to decide between the stuff on Adorama and ebay. I'm leaning toward one big enough for the 35 and a set of step-down rings to fit the other 2. Then I won't have so much to carry around.
I wonder if anything made for Bronica might happen to fit: they seem to have liked to make square, rigid ones. I forget how they may have attached. Possibly they would clip inside the filter threads.
I wonder if anything made for Bronica might happen to fit: they seem to have liked to make square, rigid ones. I forget how they may have attached. Possibly they would clip inside the filter threads.
Yes, I had thought about something like that. But, they'd be expensive and may vignette so I won't chance it unless I can find it locally and try it. Thanks.