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epack
10-Jul-2008, 18:36
I am new to this forum. :) Would like to get more insights from you.
According to my observaiton, most LF photographers are not using a lens hood. I wish to know why.

BrianShaw
10-Jul-2008, 18:48
This is my personal opinion, so take it for what it is worth: they are doing so because the either don't know better or because it is more difficult/expensive to find lens hoods than with smaller format cameras.

p.s. Welcome to the LF Forum!

epack
10-Jul-2008, 20:03
Thanks Brian for your prompt reply. Now I know this is truly a dynamic forum. If want to use lens hood, which is the best option. Someone advised me to buy from Cokin. Would like to know how you guys resolve this problem.

Walter Calahan
10-Jul-2008, 20:10
I almost always use a compendium instead of a lens hood.

One compendium will fit many lenses.

Here's an example: http://www.badgergraphic.com/store/cart.php?m=product_detail&p=1091

Think of it as a small bellows that sit out in front of your lens.

Daniel_Buck
10-Jul-2008, 20:11
cause my hand/hat/darkslide usually does good enough for me :)

epack
10-Jul-2008, 20:37
Thank you all for your help. Ebony has a lens shade clipped on the accessory shoe. I have never seen anyone use it.

Robert A. Zeichner
10-Jul-2008, 20:40
Here's an article I wrote on the subject last year. Take a close look at the examples.
http://web.mac.com/razeichner/iWeb/RAZP%20large%20pix/Shade%20pg%201.html

Vick Vickery
10-Jul-2008, 20:53
I, too, have and like my compendium shade for its versatility and ability to provide as much shading needed on a great variety of lenses; on the other hand, I find it somewhat combersome in the field where I have more of an inclination to use a hat or a dark slide. Be aware, though, that many a photo has been ruined by an intruding hat brim or dark slide edge!

Mattg
11-Jul-2008, 00:27
Robert's article prompted me to make a similar thing out of a set of Dedolight 8 leaf barndoors like these:
http://www.bhphotovideo.com/c/product/382390-REG/Dedolight_DBD8_8_Leaf_Barndoor_Set.html

It wasn't that cheap (~$120) or easy as they needed some metal work at a shop to help adapt them. If anyone wants me to take a picture I will, I've used Neodym magnets mounted in a Cokin P adaptor to hold the shade in place. Wasn't able to improve on the scrunchy concept though:)

I'm not sure about their effect on contrast given I am using a late multicoated lens but they are fantastic at eliminating obvious flair, especially at night with strong light sources just outside the picture area. People might say that I could use my hand to block such light sources but it gets hard to do that for 15 minutes or when there are multiple light sources.

Frank Petronio
11-Jul-2008, 00:31
Even though a little metal screw-in hood may not that effective, it does help save the lens from damage should it fall or get wacked. So I use a small semi-effective hood and use my body, hand, or card to modify as needed.

If you can see the light source on the front of your lens, you need to shade that side.... just look at the lens straight on after you are set up.

timparkin
11-Jul-2008, 00:46
Robert's article prompted me to make a similar thing out of a set of Dedolight 8 leaf barndoors like these:
http://www.bhphotovideo.com/c/product/382390-REG/Dedolight_DBD8_8_Leaf_Barndoor_Set.html

It wasn't that cheap (~$120) or easy as they needed some metal work at a shop to help adapt them. If anyone wants me to take a picture I will, I've used Neodym magnets mounted in a Cokin P adaptor to hold the shade in place. Wasn't able to improve on the scrunchy concept though:)

I'm not sure about their effect on contrast given I am using a late multicoated lens but they are fantastic at eliminating obvious flair, especially at night with strong light sources just outside the picture area. People might say that I could use my hand to block such light sources but it gets hard to do that for 15 minutes or when there are multiple light sources.

Hi Matt,

I'm very interested in your 8 Door Shade conversion! Any chance of posting a few pics.. I made a magnet mounted Lee wide angle shade so that it would work with my 80mm SSXL but would like to have some more adaptable from my longer lenses..

Is each flap (of the four) able to be adjusted independently?

Tim

p.s. Here is my Lee filter adaption and a little talk on why it's needed with large image circle lenses..

http://blog.timparkin.co.uk/2008/05/custom-magnetic-lee-adapter.html

Mattg
11-Jul-2008, 00:53
I'll take a photo Tim, apologies in advance for my average digi shots. It looks very much like a case of great minds thinking alike;) You adaptor is almost exactly what I've done with the magnets.

Each flap can move independently and the two smaller flaps each have two smaller leaves that can be spread to seal the box.

I am really happy to have this, it has already proved its worth in the first week that I've been using it. I recently reshot this scene because of a scratched neg and have now managed to eliminate some flare that was previously difficult to control with 3 large spotlights above, and slightly in front of, the camera.

BrianShaw
11-Jul-2008, 11:25
Thanks Brian for your prompt reply. Now I know this is truly a dynamic forum. If want to use lens hood, which is the best option.

I'm a compendium user for studio and field wtih view cameras. But I use press cameras a lot and for them I use series filters and the associated slip-on-the-lens hoods. The compendium is the best solution in my opinion; the slip-on hoods are much better than nothing. I don't like the hand or dark slide option because I've mroe than once found evidence of had or dark slide on the neg. My bad... and probably just a sign that I should practice those techniques more!

Nana Sousa Dias
12-Jul-2008, 16:42
I use my dark slide, my hat, and sometimes, a black umbrella, wich is the cheapest, biggest and best lens shade I've ever seen.

Louie Powell
12-Jul-2008, 18:04
A lens shade is a good idea, but its one more thing to have to carry.

I have a set of Cokin shades that clip onto a Cokin P-series holder. But I rarely use them because of the convenience factor.

I do carry another form of shade, however. It's a double-bulldog clip - essentially a pair of large office-style spring-type paper clips that are attached to each other through a common handle arrangement. I clip one end to the front standard of the camera, and then clip a shade to the other end.

For the shade, I could use the gray card that I carry with me. But a better choice is a small sheet of dark gray plastic foam - actually, packing material that came in a computer card box that I normally use to protect my ground glass from physical damage but that serves double duty as a shade.

Incidentally, one of the challenges for LF photographers is that we often need a shade on the back of the camera as well as the front - to keep light from entering through the slot in the film holder. I usually wear a hat when photographing, and if the orientation of the camera has that slot facing the sun, I use my hat as the second shade.

Brian Ellis
12-Jul-2008, 19:55
Contrary to what some have suggested, I wouldn't recommend using your hand, hat, or dark slide. Those things may work fine if the sun is striking the lens directly. But they're of little use when the light is more diffuse. In that situation there's no substitute for a compendium shade IMHO.

epack
13-Jul-2008, 08:32
Thank you all for your very useful discussion. What is easy and simple for small format phtography seems that complex when it come to LF. I just can't understand why LF lens don't come with a standard hood. Someone said to me that LF photographers don't suffer from issues like flare, because the lens design is different. I can't buy in that argument at all. Then if a lens hood is necessary, I beg to have a compact lens hood as seen on any lens for small format.

Frank Petronio
13-Jul-2008, 08:49
When you apply movements then you are changing the optimal depth, and position of the shade that you need, so a universal all-purpose hood will not work, it will vignette a corner of the image.

When you use a handheld 4x5, like a Crown Graphic or Technika, or any camera with limited movements, you can get away with a screw-in regular style hood like you would use with a medium or small format camera because you rarely use movements when working handheld.

When you use more extreme movements, you end up needing a flexible compendium hood, which can adjusted to have one corner extend out further than the others, or using the hat/hand/card technique to shield the lens.

In practice I just use a shallow screw-in hood for a bit of minimal protection and supplement it by blocking any obvious light source that reflects onto the lens -- using cards, my hand, or my fat ass.

GPS
13-Jul-2008, 09:30
Thank you all for your very useful discussion. What is easy and simple for small format phtography seems that complex when it come to LF. I just can't understand why LF lens don't come with a standard hood. Someone said to me that LF photographers don't suffer from issues like flare, because the lens design is different. I can't buy in that argument at all. Then if a lens hood is necessary, I beg to have a compact lens hood as seen on any lens for small format.

The fact that LF lens doesn't come with a standard hood has to do with the fact that you often use it with movements (shifts) unlike a small format lens. That leads to a bigger lens shade (together with a fact that a bigger film format needs a bigger shade)i.e. less efficient than a shade strictly constructed for a fixed lens. Also, a LF lens can be used for many different film formats demanding different hoods dimension.
The fact that LF photographers (amateurs especially) don't use a proper lens shade has to do with ignorance more than anything else.

cjbroadbent
13-Jul-2008, 13:15
One compendium, one set of filters with many rings for lenses. There's a Cokin compendium and a Lee for big lenses. It does make a difference. (For who's new: Shifts with a compedium require finesse. Squint throught the corners of the ground glass to adjust the compendium until it is touching the picture. When you stop down the vignetting goes away).

Robert A. Zeichner
13-Jul-2008, 14:45
On sunny days you have hard (sun) and diffuse scattered(skylight only), while on overcast days only diffuse light where you have less trouble.

I disagree. Forgetting about sun flare, which is an obvious issue that can be dealt with by using something like a dark slide or hat, the overall brightness of the scene is compensated for by longer exposures. An exposure that results in proper negative density might be 1/15th of a second or a couple of minutes. Just because the sun is nowhere to be seen doesn't mean you don't need a proper shade. I made two identical exposures of a black object in overcast rainy conditions, one with and one without a shade. Exposure was several seconds. The unshaded negative has noticeably less dynamic range (contrast) then the one that was shaded. In LF where we are apt to be using lenses with far greater coverage than is necessary for a straight on set up with no movements, or lenses designed for a larger format, or lenses that are only single coated or even uncoated, the right shade can make all the difference and is a important as having a good cable release and a solid tripod.

Mattg
13-Jul-2008, 19:43
Here are the promised pictures of my adaptation of the DBD8 Dedolight Barndoors, and as promised the pictures are trully terrible.

The DBD8 barndoor set comes with a flange on the rear that I had removed at a metal work shop. I tried to do it myself but soon realised I was going to make a real mess of it as the plate is made of steel (this when I thought of using magnets!).

The opening on the DBD8 is just less than 67mm (and after the work just larger than 67mm) which suited me well as that's the largest filter size I use. It will not vignette with a 65mm Grandagon; a 58mm to 67mm step-up ring is used and pictured. As far as I can tell it will not vignette on 4x5 with this lens even though I only use 6x9.

The magnets are Neodym or "rare earth" magnets that are 3mm diameter and 1.5mm deep. They are mounted into a Cokin P 67mm adapter. I just drilled 3mm holes in the soft aluminium adapted and epoxied them in. The picture shows the rear of the adaptor with step-up ring in place. I could have used 4 more magnets from the outset but the 12 that are there do the job well.

I used a piece of plastic to created a ring on the inside of the Cokin P adaptor, this helps the shade stay in place on the adaptor when adjusting the leaves and doesn't interfere with it being rotated or put on and taken off.

Hope this helps someone else who wants to make one. I haven't bothered taking any in use pictures as Robert has posted a link to his article in this thread and it works in just the same way.

GPS
14-Jul-2008, 12:05
Robert,
when ignorance is deliberate, you cannot beat it by any means... Forget about it.

Mattg
14-Jul-2008, 14:41
"The unshaded negative has noticeably less dynamic range (contrast) then the one that was shaded. "

Robert, I never said the lens is not shaded. I try to position myself so the camera is in the shade, or I use a hat/darkslide/hand, etc. I guess it falls back to preference, time for setup, wind issues. Rubber hoods are less effective then a hat (doesn't shade entire lens), and compendiums are okay if you arrive early and no wind, and I doubt a compendium works effectively with ultra wide angles. Like small wide angle hood, it's more for physical protection because it cannot shade the entire lens (while your hat can). Hats just work, they shade my lens and my head. When your in a situation where you can't see due to high flare, even your hand covering your eyes works incredibly well. That's all there is too it, and rely on multicoated lenses, top quality filters for the rest which brings up another issue....how many of us use the best filters, a first line of defense against flare?

I'm not trying to talk anyone into avoiding lens hoods or compendiums, just that I believe your hand/hat/darkslide is very effective alternative, and your aware all the time if your lens is fully shaded or not. It is a time saver, and you don't have much choice when you start using lenses with thread sizes of 105mm.

I find it interesting that we have tested a lens with/without a hood in place, so has anyone tried with hat/no hat and seen a difference?

A couple of the points you raise against compendiums are actually in favour of these kind of barn door hoods. Unfortunately I'm not sure how you'd go with one for a 105mm lens diameter. It might be quite heavy and have a bit of sail area as well.

As far as the overall loss of contrast goes that might be an advantage sometimes in that it would be like a mild preexposure and serve to increase your film speed. The disadvantage would be that you don't really have control of it.

In my case I am using lenses that cover 4x5 on a 6x9cm negative so I have a lot of spillage. That spillage is also very close to the negative because the bellows are comparatively small. I can live with lenses that have a maximum diameter of 67mm.

Most importantly there are very clear benefits when working with long exposure times and unusual lighting situations. Until now I have been holding my hand still, outstretched and up, during 15 minutes exposures. That's no fun. A shade like this does the job so much better. I really think if you can use one it's well worth doing so. The benefit of controlling the light spilled inside the camera is a welcome bonus and means I can choose when to use a prexposure.

P.S. That Peter Lik promo is pretty funny in the context of this discussion. Not only does he not use a lens hood but he runs through the surf with his panoramic camera on a tripod. He is even shown with sand and salt all over it. It seems like a clear case of Jo Blogs sticking his head in the fire to me...is this what you want to emulate? BTW he did take an enormous beach umbrella so how do we know he didn't use that as a lens shade just at the critical moment?

Frank Petronio
14-Jul-2008, 14:56
Thread just goes to show that there is a right,wrong, and about 1,958,732 other ways to do things....

Ben Syverson
14-Jul-2008, 16:38
There are plenty of times when I want to reduce contrast. I shoot with modern, multicoated lenses, which can easily send highlights and shadow areas to the extremes.

Shooting with a low-contrast color negative film like Portra 160NC or 400NC can help, but when shooting E6, even Astia, it can be hard to manage.

Since I'm rarely in the position of wanting more contrast, I don't use a shade... So I would hardly say that there is a "right" and "wrong" answer when it comes to someone's preference about hoods/shades.

Turner Reich
14-Jul-2008, 16:57
Robert and Matt I want to thank you for the terrific information about an often forgotten and or overlooked technique. Thanks for asking and welcome e pack.

Mattg
14-Jul-2008, 19:41
However, bellows flare is different problem, and due to lens coverage, I don't think a hood will change that.

Yes it will, that's the whole point of using a "hood" that's fully adjustable like these barn doors. Once adjusted so that each leaf almost cuts into your frame there is no excess light falling on your bellows. With the barn doors it's easy to make the asymmetrical adjustments you need when using parallel movements. I know it can be done with a proper compendium that has an adjustable masking system but there aren't many of those (Linhof and Sinar) and those that there are are definitely going to exacerbate any vibration problems on windy days. I've found it is usually easiest to look back through the lens at your ground glass, while stopped down to the taking aperture, and adjust each leaf so it's just outside the picture area. Takes about 30 seconds to fit and adjust.

So not only are the barndoors as effective, quicker to set up and less prone to vibration, they're also cheap in comparison to used compendium systems with masks. I'm just very thankful to Robert for sharing his idea, it is so very effective. If you haven't noticed a need for it then I don't think you absolutely have to go out and use one. I had a very clear need for it that showed up as wasted film and wasted time. The barn doors are worth every dollar and minute I spent getting them.

I think that Peter Lik video must have been a bit of a Baywatch piss-take, hilarious. I bet he's making a fortune.

Frank Petronio
14-Jul-2008, 20:14
I never heard of the guy in spite of his worldfamousness. And did you see the size of his book? It was ridiculously over-sized for a bunch of generic sunsets. Does he actually sell it to crazed Aussie tourists? Damn it can't be cheap.

That and he seems to better portraits of himself in action gear than his own photography. He looks like a porno actor.

Or is it all just a joke? His stuff is so slick I keep waiting for the ironic punchline.

Mattg
14-Jul-2008, 20:44
I never heard of the guy in spite of his worldfamousness. And did you see the size of his book? It was ridiculously over-sized for a bunch of generic sunsets. Does he actually sell it to crazed Aussie tourists? Damn it can't be cheap.

That and he seems to better portraits of himself in action gear than his own photography. He looks like a porno actor.

Or is it all just a joke? His stuff is so slick I keep waiting for the ironic punchline.

You missed the joke Frank, he sells it to American tourists.

I say good on him. Making his photography a mass market commodity while charging exclusive prices; very clever. His self promotion video; priceless.

Mattg
14-Jul-2008, 22:34
My point is if your using a lens for 8x10 on say a 4x5, then the lens is likely projecting the image on to the bellows because of the very wide lens coverage (that accounts for 98% of the light on bellows I believe). You won't fix that with a compendium.

Yes you will, that's why they're made for large format photography. An adjustable mask system at the front of a compendium can be used to limit the area of the opening. The barndoors do the same thing. You aren't limiting the opening to the edge of your lens' image cricle, you're adjusting them to match the image projected on the groundglass.

Technically the lens is still projecting onto the bellows but now the only image being projected outside the film area is the image of the black inside of the barndoors or compendium. In other words very little light at all.

epack
15-Jul-2008, 00:22
Ebony sells an elegant lens shade clip which can be installed on the accessory shoes. With the lens shade clipped on, focusing cloth can be placed on top of the shade. It is like erecting a little tent over the lens. I don't know if it works.

Robert A. Zeichner
15-Jul-2008, 01:47
Frank, your right, and said it best.

Mattg, I see your point with longer exposures. However, bellows flare is different problem, and due to lens coverage, I don't think a hood will change that.

Bellows flare is completely eliminated with a barn door type shade. When you make your adjustments while looking through the clipped corners of your ground glass, you are actually masking off any light that gets projected beyond the film, leaving no projected light left to strike the bellows. The best part is that you are doing it up front which has the added benefit of preventing any non-image-forming light from ever getting inside the lens where it can, in many instances, rob you of contrast.

cjbroadbent
15-Jul-2008, 05:31
Epack,
The Ebony clip works OK when you're using screw-in filters. I use a film box lid for a barn door. But it's a bad idea to drape the black cloth over the clip. Murphy's law. Better get a Cokin compendium.

Jim Cole
15-Jul-2008, 07:00
As to the comment about never having seen anyone using the Ebony lens shade holder that clips to the accessory shoe, I do use it. It works great with the black ground glass protector that came with the camera. Simple and easy to adjust before making the shot.

timparkin
15-Jul-2008, 09:29
Ive used the ebony card and lee compendium style filters. I've also done a few measurements and know what size shade to use.. The web pages show just how much extra image forming light you get with some lenses..

http://blog.timparkin.co.uk/2008/02/lens-hoods-and-filters.html

also just to prove you can use a lens hood on an 80mm lens with a centre filter and still use a polariser if you want..

http://blog.timparkin.co.uk/2008/05/custom-magnetic-lee-adapter.html

OK, maybe it is slightly customised..

Tim

p.s. Mr Lik has a cool sense of humour (I think) and, thankfully for him, American tourists don't. He also must be very confident in his insurer to do surfrunning with his camera - mind you at 20m dollar annual turnover, the camera cost is irrelevant..

GPS
15-Jul-2008, 09:31
Bellows flare is completely eliminated with a barn door type shade. When you make your adjustments while looking through the clipped corners of your ground glass, you are actually masking off any light that gets projected beyond the film, leaving no projected light left to strike the bellows. The best part is that you are doing it up front which has the added benefit of preventing any non-image-forming light from ever getting inside the lens where it can, in many instances, rob you of contrast.

Unfortunately, things are not so easy as you say, Robert. You're right saying that the belows flare is eliminated when the lens only projects the light on the film format area. But it doesn't mean that "any non-image forming light" cannot get inside the lens and on the film format. The non-image forming light still can get on the lens surface, depending on the lens shade length. The longer (and, consequently, bigger) the lens shade is, the more effective it is in cutting off the stray light. But to completely eliminate it is an entirely different thing.
Fortunately, a lens shade can have a great effect on the picture even before complete elimination of the stray light. A hat can never have the same effect for obvious reasons...

cjbroadbent
15-Jul-2008, 10:24
With Ektachrome, before Photoshop and in extremis, a few of us laid a white card inside the bellows to catch some sky. It softened-up the dark parts without messing with the high-lights. I suppose you could call that pre-flash - but at least it was proportional and of the right colour. My 5x7 box was getting the same effect because extraneous light bounced off the smooth insides at just the right angle to hit the film. That was fixed that with corrugated black paper.
I would suggest that a bellows camera is less vulnerable to glare than a Medium Format camera. White backgrounds (2 stops over) with a Hasselblad have always required some sort of compendium on the lens rather than the ordinary lens shade - and even then. But with a 4x5, no wishy-washy at all.

Robert A. Zeichner
15-Jul-2008, 19:47
Unfortunately, things are not so easy as you say, Robert. You're right saying that the belows flare is eliminated when the lens only projects the light on the film format area. But it doesn't mean that "any non-image forming light" cannot get inside the lens and on the film format. The non-image forming light still can get on the lens surface, depending on the lens shade length. The longer (and, consequently, bigger) the lens shade is, the more effective it is in cutting off the stray light. But to completely eliminate it is an entirely different thing.
Fortunately, a lens shade can have a great effect on the picture even before complete elimination of the stray light. A hat can never have the same effect for obvious reasons...

Actually, the barn door shade does prevent non-image forming light from hitting the surface of the lens. You can see this when you check the corners of the gg. You adjust each leaf of the barn door until it just cuts into the viewable area of the gg and then you back it off a bit so you don't vignette. I think you need to read the article carefully. http://web.mac.com/razeichner/iWeb/RAZP%20large%20pix/Shade%20pg%201.html

GPS
15-Jul-2008, 22:44
Actually, the barn door shade does prevent non-image forming light from hitting the surface of the lens. You can see this when you check the corners of the gg. You adjust each leaf of the barn door until it just cuts into the viewable area of the gg and then you back it off a bit so you don't vignette. I think you need to read the article carefully. http://web.mac.com/razeichner/iWeb/RAZP%20large%20pix/Shade%20pg%201.html

What you need is to think more about the geometry of a lens shade before you start with claims that are not true, Robert.
At the edge of a barn door a light ray can hit the surface of a lens under an angle grater than the angle of view of the given lens. This light ray causes flare. A question of geometry.
If you think a lens shade can eliminate all the non image forming light hitting lens surface you're mistaken.

Mattg
15-Jul-2008, 23:00
Hi GPS, could you please try to explain it for me, I'm afraid I don't understand. If the barn doors are adjusted properly, what light is reaching the lens? Isn't any light that reaches the lens in this case going to appear on the film?

Light can strike the inside of the barn door leaves but these are ideally black velvet and absord a lot of light so we might assume they are contributing almost no light.

GPS
15-Jul-2008, 23:08
It's quite easy. In order to eliminate the stray light hitting lens surface it is not enough to limit the lens angle of view in such a way that the angle of coverage will match the film format. You could do that with black ink on lens surface. Would that eliminate the non image forming light from hitting the lens surface? Of course not.
The lens shade geometry is more complicated...

Mattg
16-Jul-2008, 00:09
I'm still lost. The black ink example doesn't make much sense to me in this context. It would be like having a lens shade with a length approaching zero. The barndoor shades we're talking about have a length considerably more than zero and, as far as I can see, have the practical effect of excluding very nearly all non-image forming light.

I can see that a little bit around the edges where you adjust the shade to prevent vignetting will reach the lens but you seem to be talking about something else. Please describe for me how a ray of light that will not be focussed on the film reaches the lens with a shade properly set up.

timparkin
16-Jul-2008, 01:19
What you need is to think more about the geometry of a lens shade before you start with claims that are not true, Robert.
At the edge of a barn door a light ray can hit the surface of a lens under an angle grater than the angle of view of the given lens. This light ray causes flare. A question of geometry.
If you think a lens shade can eliminate all the non image forming light hitting lens surface you're mistaken.

I have to agree here because there will always be a an amount of light hitting the lens that is non-image forming. Only an infinitely long lens shade and an infinitely small aperture will assure this.

However, there is no difference between a hand shading a lens and a lens hood. The hand can just be thought of as a section of an imaginary lens hood that just happens to block the sun. Yes, in some situations where the sun is only a few degrees out of the shot you can hold your hand 5ft away from the camera and shade the lens where it would be difficult to do so with a lens hood. However, in that situation, the sky around the sun is still very intense and, if your subject isn't similarly bright, could cause veiling flare and bellows flare. Rember, you've only blocked the disc of the sun, not the sky nearby.

If I'm taking a picture with the sun only just out of shot, I'll check the front of the lens is shaded with the lens hood. If it's not, I'll try to use my hand. However, if it's that close to the edge of the frame, it's very likely I'll end up vignetting the shot with my hand.



Fortunately, a lens shade can have a great effect on the picture even before complete elimination of the stray light. A hat can never have the same effect for obvious reasons...


I'm not sure I get this. Are you saying that the hat has some magical property that stops it vignetting pictures? As far as I undertand things, the hat is just blocking the sun in the same way a shade would. If the shade was going to vignette in a certain position, so would the hat. Could you explain the obvious to me?

Tim

p.s. I should have said that for non-infinite apertures, the edge of any lens hood or hat will be blurred on the image plane. This means that to exclude any element of the hat or hood, you have to position it so the edge of the blur is outside the picture. This means that light from the blurred area is non-image forming but will still be entering the camera.

Mattg
16-Jul-2008, 01:32
I have to agree here because there will always be a an amount of light hitting the lens that is non-image forming. Only an infinitely long lens shade and an infinitely small aperture will assure this.

....

p.s. I should have said that for non-infinite apertures, the edge of any lens hood or hat will be blurred on the image plane. This means that to exclude any element of the hat or hood, you have to position it so the edge of the blur is outside the picture. This means that light from the blurred area is non-image forming but will still be entering the camera.

Yes, where you adjust to avoid vignetting a small amount of excess light will get in as I mentioned in my previous post. I'm not sure of the meaning of your first paragraph though Tim.

Please put me out of my misery and explain how a ray of light that will not be focussed on the film can still fall on your lens if each of the 4 leaves of the barndoor are correctly adjusted.

timparkin
16-Jul-2008, 02:36
Yes, where you adjust to avoid vignetting a small amount of excess light will get in as I mentioned in my previous post. I'm not sure of the meaning of your first paragraph though Tim.

Please put me out of my misery and explain how a ray of light that will not be focussed on the film can still fall on your lens if each of the 4 leaves of the barndoor are correctly adjusted.

OK.. Let's imagine that you set the barn doors tight enough that you can see them. At your taking aperture, you will see that the edges of the barn door are blurred.

You really don't want to include any of these edges in your picture because you will get darkening in your picture. So.. you open up the barn doors until you can see any of the blurred edges.

At this point, the light that is part of the blurred edge is hitting the lens and getting through to the inside of your camera but is not hitting your film/gg.

This effect is really obvious when your aperture is wide open.

Tim

p.s. I'll do a diagram if this doesn't make sense..

Mattg
16-Jul-2008, 02:42
OK.. Let's imagine that you set the barn doors tight enough that you can see them. At your taking aperture, you will see that the edges of the barn door are blurred.

You really don't want to include any of these edges in your picture because you will get darkening in your picture. So.. you open up the barn doors until you can see any of the blurred edges.

At this point, the light that is part of the blurred edge is hitting the lens and getting through to the inside of your camera but is not hitting your film/gg.

This effect is really obvious when your aperture is wide open.

Tim

p.s. I'll do a diagram if this doesn't make sense..

No that's easy enough to understand Tim, as I said last post, I've already described that situation here a couple of posts back. I'm trying to understand GPS' point about other sources of non-image forming light and thought you were on a similar tack.

E. von Hoegh
16-Jul-2008, 03:30
I am new to this forum. :) Would like to get more insights from you.
According to my observaiton, most LF photographers are not using a lens hood. I wish to know why.

I'd like to know why, also. I use alot of old uncoated lenses (Dagors) so I consider a compendium mandatory. When I was working professionally, I often used the old lenses - the customers were always happy. Just keep in mind, that the most valuable equipment is between your ears. I have one of the vaunted 14" multicoated Gold Dot Dagors, and THAT benefits from a compendium! Properly adjusted, a compendium will also reduce bellows flare.

Welcome to the forum, and welcome to the wonderful world of Large Format!

GPS
16-Jul-2008, 03:32
Mattq: As you correctly said - an inked lens would be a lens shade with a zero length. It would still limit the lens field of view for the lens covering angle equal to the film format. Yet, as you know, it would not act satisfactorily as a good lens shade. If you make the lens shade just a few mm long, with the same limits for the field of view it will act as a better lens shade... still a longer lens shade will act even better... They all limit the field of view for the angle of coverage made just for the film format. Yet their efficiency against flare is not the same. Why? Robert incorrectly thinks that it is enough to limit the field of view with barn doors so that the lens covering angle matches the film format and the shade eliminates the stray light "completely". In the example above all lens shades limit the field of view in this way - yet, they have different success in acting as a lens shade. Why?
Take a point light source, and at the edge of the lens shade incline it in such a way that it hits the lens surface. You'll see that the angle of this light ray is greater (axially) than that of the field of view and yet it hits the lens. Make a diagram to see.
The longer the lens shade is, the better it shields against this stray light (it limits its angle) but it never eliminates it completely. Hence...

Tom: A hat is just one side of a lens shade which itself has 4 sides... The flare causing light doesn't come only from the sun. It's all over, 360° around the lens axis - lakes, sky, a white or less white wall, etc. Try to cut that stray light hitting the lens with a hat... better than a 4 sides lens shade does... Enough said.

GPS
16-Jul-2008, 03:41
Ehm, Tom is Timparkin in above...;-)

timparkin
16-Jul-2008, 04:24
Tim: A hat is just one side of a lens shade which itself has 4 sides... The flare causing light doesn't come only from the sun. It's all over, 360 around the lens axis - lakes, sky, a white or less white wall, etc. Try to cut that stray light hitting the lens with a hat... better than a 4 sides lens shade does... Enough said.

Yep, that's exactly what I was saying and wrote my blog post about...

Robert A. Zeichner
16-Jul-2008, 04:52
Mattq:Robert incorrectly thinks that it is enough to limit the field of view with barn doors so that the lens covering angle matches the film format and the shade eliminates the stray light "completely".

Not so. If you read the paragraph titled "Refinements" on the second page of my article you will find this:

"...The second thing I noticed was that
when shooting into the light in some
situations, it might be handy to have
an extension of the top barn-door leaf
that could be unfolded to cast a longer
shadow on the front of the lens. I was
able to tape a piece of black card stock
to the top leaf with 3M #235 photo-
graphic tape."

GPS
16-Jul-2008, 08:53
Bellows flare is completely eliminated with a barn door type shade.
-snip-
The best part is that you are doing it up front which has the added benefit of preventing any non-image-forming light from ever getting inside the lens where it can, in many instances, rob you of contrast.


Actually, the barn door shade does prevent non-image forming light from hitting the surface of the lens. You can see this when you check the corners of the gg. You adjust each leaf of the barn door until it just cuts into the viewable area of the gg and then you back it off a bit so you don't vignette. I think you need to read the article carefully. http://web.mac.com/razeichner/iWeb/RAZP%20large%20pix/Shade%20pg%201.html


Not so. If you read the paragraph titled "Refinements" on the second page of my article you will find this:

"...The second thing I noticed was that
when shooting into the light in some
situations, it might be handy to have
an extension of the top barn-door leaf
that could be unfolded to cast a longer
shadow on the front of the lens. I was
able to tape a piece of black card stock
to the top leaf with 3M #235 photo-
graphic tape."

Robert, as I said, your first statement about the elimination of "any" stray light from hitting the lens surface is not correct. This incorrect statement you tried to defend with you second quote where you left out the "any" stray light.
Now you try to say you know that there isn't any elimination of all the stray light with a lens shade. Decide for yourself which statement you want to defend and stick to it.

When it comes to your described extension it acts as a longer (a more efficient but again, not eliminating all the stray light) lens shade. With the disadvantage that it does so only on one side of the shade (like a hat...). It's a sort of a compendium shade on one side only...
No lens shade, however long, can entirely eliminate all the stray light. The theoretical 100% efficiency would demand a lens hood protruding beyond the parasitic light source (which is all around the lens in one way or the other).

This said, a lens shade can be highly effective even if the parasite light is not 100% eliminated. A hat can never do that.
I calculate my lens shades with theoretical 60 -75 % efficiency - more than enough to see the dramatical improvement in image formation.

GPS
16-Jul-2008, 09:11
Yep, that's exactly what I was saying and wrote my blog post about...

"There is one who sees..." Remember that film with the man talking to his watch? I loved that...:)

timparkin
16-Jul-2008, 09:21
"There is one who sees..." Remember that film with the man talking to his watch? I loved that...:)

/me shakes head in apparent agreement

CG
16-Jul-2008, 13:02
I love really good lens shading too, and use Sinar's bellows as a compendium shade and Lee's shade a lot too, but this horse is in danger of becoming a dead bloody pulp.

C

GPS
16-Jul-2008, 13:15
I love really good lens shading too, and use Sinar's bellows as a compendium shade and Lee's shade a lot too, but this horse is in danger of becoming a dead bloody pulp.

C

Heck, I have to speak to my watch again. "There is one here, who sees..." :)

timparkin
16-Jul-2008, 13:49
1. Wind vibration- how many shots were slightly blurred under low/moderate/heavy wind. I shoot ocean scapes, that compendium is useless in many cases. Check Phillip Plisson who specializes in these types of images. That compendium would get ripped right off the camera. This guy sells tons of images, and they don't look low grade to me in galleries blown up to 50 inches. With his photos he rarely has the opportunity to even use a hat unless he wants to lose it from the heli. Lets get practical!


Wow!! The guy uses a large format camera from a Helicopter - and he managed to fit it inside a canon SLR!!? With a lens hood on??!!

Seriously, if we were worried about missing the shot because of wind, we wouldn't be using large format cameras..



2. Time constraints- number of shots lost due to using vs not using one. I would rather
get the right light then 30 seconds too late. If you have the time...great.


We're using large format cameras! If we were time critical we'd use SLR's or Mamiya 7's!!



3. Head count test- lets count up heads and see how many use one in the field all the time vs sometimes vs none vs preferring hat/hand/card or equivalent. I think you will find it used very little outdoors. In fact Alain Briat shows his complete set up for his 4x5 and 617 outfits that he takes into the field---not one mentioned. Hmmm? He forgot the compendium, but not his GMRS radios.


So Alain is the "Canonical Large Format Photographer"? He's good but I don't think any photographer is in the league of "If you don't do what I do, you're doing it wrong"

I know two professional professional photographers (and a rank amateur - myself) who have had pictures ruined through bellows flare caused by non-direct light. One picture was in Namibia at a place called Deadvlei. The sun was rising and he'd taken a shot in the shade of a dune. The dune above the one he was taking was in full direct sunlight, there was a significant bellows glow on the final picture. The other taken over water where the water had many high intensity specular reflections, the picture was over the water into an area of shadow.

In other words, you should know when you need one and use it - otherwise you *risk* ruining a potentially killer photo**... (note my highlighting of the word risk - not you *will* - just you *risk*)

** Not that I've had the opportunity to make this mistake yet!



4. Bellows design- could it be the materials used, shape, just a few cameras that speak for the rest as if scientific fact. The theory is correct, but is it a real and significant problem outdoors, enough to degrade my images so their not usable? I just don't see people complaining in here about bellows flare, but I do about pizza wheel marks, red issues, inks, vista, etc.


Perhaps it's one of those subtle differences that people don't notice, like obscure chemical use in developing. People who don't bother don't see a problem because they don't know there is a problem. I've seen many photographers not shade there lens front element.. Does this mean they won't take any good pictures? No! Does this mean that flare affects every picture? No! Does this mean that some pictures will have reduced contrast for reasons they don't understand? Possibly! Does this mean that some pictures will get ruined because of flare? Probably!

You debating style is all over the place. You have a point, most people get away without using compendiums. Don't try to turn that point on it's head and suggest that compendiums are irrelevant. You may choose not to use them and you may be right for your needs. Other people choose to use them because they see or feel they receive a benefit..



I totally support using a compendium for studio use when you have the time to set it up, high key shots, or in the field if you arrive early, otherwise.....noooo way!


Theory is one thing, I would spend more time worrying about getting the next picture. For the 10% of the time I need one a hat is good enough for me, and I am certainly not going to wast my time setting up for the 90% of the time I don't need one.

Good for you!

Tim

Frank Petronio
16-Jul-2008, 14:43
An utterly amazing thread guys... here is the original question from the new guy:


I am new to this forum. Would like to get more insights from you.
According to my observaiton, most LF photographers are not using a lens hood. I wish to know why.

I hope he isn't scared away!

timparkin
16-Jul-2008, 15:11
An utterly amazing thread guys... here is the original question from the new guy:

I hope he isn't scared away!

He's probably hiding behind his hat (or inside his lens hood) :-)

For the original poster..

I think most people don't use them because they haven't experienced the need for one or perhaps they only use them rarely when they really see the need. Also, they're not cheap and are a faff to use.. Finally, if you don't know what you are doing with a lens hood/compendium shade, they are probably worse than just using your hand. In the majority of situations, your hand or a clip on shade is enough anyway.

As an interesting aside, a couple of professional photographers I know always end up having their publicity shots in front of a camera with no lens hood even though they nearly always use one? It's probably because most publicity shots are taken when somene isn't really taking a proper picture..

p.s. here is a photo of Christopher Burkett using a compendium hood. He also has lots of photographs where he isn't using one.. If there is a list who really know about getting the best quality prints out of a large format camera, he has to be up there at the top. If he's using a compendium, I think he'd have a reason.

http://www.christopherburkett.com/pages/behindscenes/galg.jpg

http://www.christopherburkett.com/pages/behindscenes/cbschnauzerslg.jpg

Mattg
16-Jul-2008, 17:20
An utterly amazing thread guys... here is the original question from the new guy:
I hope he isn't scared away!

If you're not scared off by the thought of Peter Lik running at you with a beach umbrella you can handle this.

I'm satisfied that my new hood "effectively" excludes "almost all" non-image-forming light and am very glad I chose to make one. Thanks Robert.

epack
16-Jul-2008, 22:22
Thank you for all your replies! I am not scarred away, intead I am reading all your posts, learning a lot. When recalling his early days in Canada as a school boy, Yousuf Karsh said:" I suppose there is no loneliness greater than that of a boy at a new school...."
This forum is a new school for me, but I experience no loniness at all. I feel at home.

m.bruehl
17-Jul-2008, 15:05
Hi epack,

my answers:

- lens shades fit to a lens, compendium may fit for all (on SINAR it does)
- easy to set copal shutter, if needed:adjust filter, then just move back compendium towards lens - that's it

I never go without. In my opinion easiest way to improve picture quality (or not to reduce it). It's ready in my bag, just put in slot, close holding screw and adjust length and angle. O.K., if these 30 secs spoil an image - bad luck. Didn't happen to me up to now.

If wind is a problem, you have to shield the camera as well as the compendium.

Many people discuss and compare lens qualities like resolution in lpm. Or how parallel darkslides fit to lens plane. Or how flat film lies in darkslides. Or any other thing that is out of your influence. I would like to know if these people are the same that don't see the advantages of a compendium ...

You may improve images by a simple compendium. So why throw it away?

Regards

Michael

erie patsellis
17-Jul-2008, 15:55
Hi epack,

my answers:

- lens shades fit to a lens, compendium may fit for all (on SINAR it does)
Though the 360 6.8 is a tight fit, at best. It requires some gymnastics, akin to putting a large round peg into a smaller square hole.



- easy to set copal shutter, if needed:adjust filter, then just move back compendium towards lens - that's it
<snip>
Regards

Michael

Or not so easy to set #3 Copal shutter, without removing the shade nearly all the way, one of the reasons I've been transitioning to DB mounted lenses and the Sinar Shutter, in fact.

Add a properly adjusted Bellows Mask and it's a nearly bulletproof way to shade a lens, in spite of the "sail" tendencies, I'll wait for a lull myself, or block the wind with my body/umbrella, etc.

erie

andress007
22-Dec-2008, 17:32
R. Avedon lens hood :)

Chris623
22-Dec-2008, 20:30
I always used a bellows type lenshood back when I was active in LF. It was articulated and allowed me easy use of rise and fall. Don't know the brand, as it's not marked and I bought it at a photo show back in the middle 70's. But I wouldn't shoot a picture out in the sunlight without it.

jeroldharter
22-Dec-2008, 21:26
The fact that LF photographers (amateurs especially) don't use a proper lens shade has to do with ignorance more than anything else.

Not exactly. The compendium for my camera costs more than $800 (Arca Swiss) and they are rarely available used. My left hand is only worth $700 so I can't even trade it in. So until until the Large Format Photographers in Crisis union gets its multi-billion dollar government bailout so that we can all get the compendium shades that we deserve, I will be using my hat.