How do you use a lens hood best?

[pmazolo]

Hi,
I do use a hood for my Sinar, and bought one for my ne Wista 45SP. However, I am never quite sure how to best use them...that is, how far to extend it....pulling it out until I get vignetting is one idea, but if you move your finger at the edge of the hood you will see that the image is affected much "earlier" that you think.... How to optimize this? Is this a strange thing to think about? Have I missed some obvious basic technique here?
Rgds
PM

[pmazolo]

I am not alone...;-) Have found another nerd who obviously gave this some though:

http://www.vanwalree.com/optics/lenshood.html

How do you set up the compendium hood in practise (those of you who use it)?

Rgds
PM

[pmazolo]

Check out this link from the artice:

http://www.vanwalree.com/optics/lenshood/hasselblad_avoiding_flare.pdf

/PM

[Robert A. Zeichner]

Not being a Sinar user, I don't know if your ground glass has clipped corners, but on my Deardorff, I can sight through the corners at the lens aperture to see if vignetting is taking place. This, I beleive is the only way you can be absolutely sure. It is important to make this observation at the taking aperture. At larger apertures, you will need to draw the shade back closer to the lens. Of course, if you want to exclude all non-image forming light, you will not accomplish this with a square format shade, as you will reach the edges of the short dimension of your film before the long dimension. Sinar did make an incredible contraption that worked like a matte box in front of the lens. It had individual adjustment curtains on four sides and an adjustable bellows. That would have to be the ultimate shade and, I'm guessing, the most costly. But, what's cost to a finatic?

[David A. Goldfarb]

I do what Robert Zeichner recommends, but would add that if you don't have a groundglass with clipped corners, you can sight the corners of the groundglass in the opposite direction by looking through the lens from the front of the camera.

[pmazolo]

Thanks! Didnt know that about the cut corners! Will give it a try..... however, according to the later link, you can allow some of the hood to be visible in the corner, as the light falling in that part of the film comes from other vectors too....thus a small vignetting might be worth having....or something like that...../PM

[Robert A. Zeichner]

Here are some photos of my barndoor shade. Very simple, fairly lightweight and extremely effective. Note the position of the barndoors on the "barn_door_shade_2" picture! This is adjusted to eliminate all non-image-forming light on a 4x5 using a 14" Commercial Ektar without any vignetting! Adjustment was confirmed by sighting through the clipped corners of the ground glass.

[pmazolo]

...Sinar did make an incredible contraption that worked like a matte box in front of the lens. It had individual adjustment curtains on four sides and an adjustable bellows. That would have to be the ultimate shade and, I'm guessing, the most costly. But, what's cost to a finatic?

Well..... So thats what it is. I have one! Been wondering what its for...;-) Wow! Lets see if I can use it on my Wista 45Sp too.....

Otherwise the barndoors seem good.

I did also buy an expensive compandium for the Wista. Will give it a try with the corner technique....so far so-so...hard to find an angle that will see through the corner and lens...and then the background seems to have to be vary bright...

/PM

[C. D. Keth]

One thing I've been meaning to do is make a set of hard mattes for my 4x5 that will go in a filter slot in a mattebox I altered to fit. Hard mattes are just bits of black plastic or metal with a cutout of just the size and shape as to block all non-image-forming light from the lens. They do wonders for contrast, especially with single or uncoated lenses. You just carry one for each lens and it saves you the time of adjusting a shade every single time. If you do this, you should use a mattebox that allows you to slide filters in the box somewhat. That will let you adjust the matte properly when you use rise, fall or shift since these essentially change the lens axis for what is imaged.

[pmazolo]

Tried the matte "corner-looking" technique outside yesterday, and I cant say it works at all for me. No way to see through, especially if the subject is not bright sky....

So, will try the looking through from front technique now....

Have an idea to put a little ruler on my compendium, with markings for my lenses. And then also cut out two black pieces of paper with velcro to block out the "long side" of the format too since the compenduíum is square. With some markings for the lenses too. With movements this has to be moved naturally, but as a quick starting point.... good idea?

/PM