Lens hoods.

[Mike Kennedy]

I was given 4 metal lens hoods of various lengths.How can I be assured that I don't vignette a certain lens.Is there a chart?

 

[Konical]

Good Morning, Mike,

The standard check is to open the shutter and look through the corners of the film frame. If there is some darkening visible, the hood is interfering. The effect will also vary with the aperture used. On a 35mm or MF camera, it's simple enough to expose a few frames with the hood(s) attached to the lens. Shoot frames at full aperture, stopped down to mid-range, and stopped down completely; the developed film should tell the story.

Konical

 

[Nick Zentena]

I think I remember a thread on optimal lenshood . It included a formula.

A wider lens will need a shorter or wider hood. I find this easier to understand if I start drawing lines on paper.

 

[Mick Fagan]

Konical has the right answer, I would just add that if possible, shoot a totally clear sky.

Then when you view your negs on a light box (or window) under a loupe, you should be able to see any damaging density differences in the corners.

Actually you don't really need a loupe to get the overall picture, but it can help for nit picking.

Mick.

 

[Jeff Kubach]

Usually you should avoid vignette image, but one day a while back I decided to a lens hood for a mild telephoto on a 17 mm lens to see what will happen. The image was a circle and I thought it was kinda neat.

Jeff

 

[Mike Kennedy]

I'll try that with the 24mm Nikkor.........................when I pay it off.

 

[tessar]

According to a Nikon catalogue I have, the correct Nikon hood for a 24mm is the HN-1 (which coincidentally is also right for the 35mm PC lenses, so as not to vignette when the lens is shifted). The diameter of the HN-1 is 71mm, the depth (from front to where the thread starts) is 12mm.
The 24mm Nikkor is one of my favorite lenses.

 

[Vanishing Point Ent.]

There is a first check that will cost you nothing in film & it will show if the hood may, ( not will ), vignette.
It is Pass, Fail. That is, if you pass, you can go on & check it with film, as was suggested above. If you fail, it's definite.

With the filter on the lens, ( distance matters ), keep the focus at infinity, manually stop down the lens all of the way & check all 4 corners, of the viewing screen, inside of the finder. If the corners are dark, even in a little, you failed.
Admittedly, this is sometimes hard to see.

If it helps, I often stack a B+W KR 1.5 filter & a Tiffen Thin Circular Polarizer together, then test.
I like to be able to twist the hood to adjust the polarizer. i find it's much easier to work this way.

 

[nicefor88]

Konical is right, his procedure works fine but sometimes it is quite hard to detect loss of light in corners with bear eyes. But your film will!!
My technique is quite simple. A lens hood for wideangle lenses 24 to 35mm shoud have a 1.5 cm depth max. Allow 5cm for a standard lens, 7cm for 85-105mm, 9cm for 135mm. These are average depths.
I have noticed that a 5cm-deep hood on a 135mm works well enough.
Of course, the position of the camera matters a lot, the closer to the light source the more chances to have undesirable light coming into the lens and fooling the meter.