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480sparky
24-Dec-2015, 10:03
On occasion, I've had need to shoot LF looking straight up. I got thinking about using a mirror at a 45 in front of the lens.

So I thought I'd ask if anyone has come up with a solution that 1. works, 2. is compact and portable and 3. durable enough to last more than 1 or 2 uses.

Kirk Gittings
24-Dec-2015, 10:18
I'd think you would lose some image quality unless you had a really expensive optical quality mirror?

cowanw
24-Dec-2015, 10:20
There are process lens mounted on mirrors for looking at 90 degrees. I have a 10 inch velostigmat like this.

LabRat
24-Dec-2015, 10:31
There are also prisms that were used on some process lenses, and in copiers... But they can get a little heavy, and are for longer FL's...

Steve K

Jac@stafford.net
24-Dec-2015, 10:34
A locking gimbal along with a 90 degree ground glass viewer is another idea. If you are handy you could make a sky camera as I did from a research project.

143939

480sparky
24-Dec-2015, 11:20
I'd think you would lose some image quality unless you had a really expensive optical quality mirror?

That's a given, but I have access to quality glass. So the iq loss would be minimal.

Stephen Thomason
24-Dec-2015, 11:33
A process lens 90 degree viewer. I have one if you are interested - my 14 inch Goerz Red Dot Artar was mounted to it. It's too heavy to just hang off the end of your lens, I would think. It would last forever, to answer part of your question. It IS compact. In use, it was mounted to a VERY heavy metal lens board about a foot or so square.

I really don't know how practical that would be for you. If you could mount it to a lensboard and use a separate standard to support it, it might work. It is indeed a nice piece of optical glass.

Another solution might be to use a mirror from a medium format parts body (or just buy a replacement mirror from eBay) and mount it in a PVC elbow (a three incher or so, black PVC). Drill and tap it and use nylon bolts to tighten the elbow to the lens. THAT I think might just work.

480sparky
24-Dec-2015, 11:45
A mirror on the back side is going to be rather problematic.......... how do you focus, for one thing?

480sparky
24-Dec-2015, 11:46
..........mount it in a PVC elbow (a three incher or so, black PVC). .........


....................................................http://i214.photobucket.com/albums/cc172/480sparky/Emoticons/CalvinBlink2.gif

Think about that for a moment................

Drew Bedo
24-Dec-2015, 14:50
I found a Spiratone mirror attachment and used it on my 4x5. I was trying for an overhead view of a still life arrangement. It worked well but was awkward for up-close use.

If you are imaging a ceiling I would think it would work fine.

http://www.ebay.com/itm/SPIRATONE-CIRCO-MIRROTACH-90-DEGREES-ANGLE-MIRROR-LENS-/121783547961?hash=item1c5add7839:g:iywAAOSw9mFWGGX5

That's one of several on e-bay right now.

Bob Salomon
24-Dec-2015, 15:42
If you have a Linhof 23, 45 or 57 a Linhof Right Angle Finder will work perfectly. If you don't have a Linhof they will not mount to your camera. Wista also has right angle finders for their cameras that will do this as does Sinar.

Jim C.
24-Dec-2015, 15:52
Keep in mind that any mirror would ideally be a front surface mirror
Normal mirrors, depending on the thickness of the glass might "ghost"
the reflected image.

480sparky
24-Dec-2015, 15:54
I found a Spiratone mirror attachment and used it on my 4x5. I was trying for an overhead view of a still life arrangement. It worked well but was awkward for up-close use.

If you are imaging a ceiling I would think it would work fine.

http://www.ebay.com/itm/SPIRATONE-CIRCO-MIRROTACH-90-DEGREES-ANGLE-MIRROR-LENS-/121783547961?hash=item1c5add7839:g:iywAAOSw9mFWGGX5

That's one of several on e-bay right now.

Yeah, but they only work with longer lenses. I'm wanting something that will work with z w/a.

pierre506
24-Dec-2015, 16:37
Sinar had such kind of design.

Bruce Barlow
24-Dec-2015, 16:44
Paul Strand did it to make street portraits, such as the one of the blind woman.

Drew Bedo
25-Dec-2015, 21:05
IIf you are going to DIY something. The Polaroid SX-70 and the cheaper One Step have salvagable front surface mirrors.

Tracy Storer
25-Dec-2015, 22:47
We have used front surface mirrors to shoot straight down for decades in the 20x24 studio. Get good quality, thick glass, thin ones warp like a funhouse mirror. Mount it at 45 deg, don't burn a hole in yor bellows or retina with infinity image of the sun.

Drew Bedo
26-Dec-2015, 07:43
. . ., don't burn a hole in yor bellows or retina with infinity image of the sun.

Could work for star trails maybe?

Emmanuel BIGLER
26-Dec-2015, 07:59
Front surface mirrors of good optical quality are not necessarily expensive.

The grade needed for taking pictuees corresponds to what is available from, e.g. Edmund Optics, "4-6 lambda" type.
http://www.edmundoptics.com/optics/optical-mirrors/flat-mirrors/4-6-wave-first-surface-mirrors/2077/
example of prices: $26 for a 85x110 mm size, $51.50 for 169x194 mm.

Ordinary "bathroom" mirrors metallized on the back side are not suitable for our photographic use, and on the opposite side of the price list, "sub-lambda" ultra-flat mirrors are overkill and too expensive; such precision mirrors will not bring any significant improvement of image quality for taking a LF picture.

480sparky
26-Dec-2015, 08:33
We have used front surface mirrors to shoot straight down for decades in the 20x24 studio............

How do you mount the mirror to the camera/lens?

Stephen Thomason
26-Dec-2015, 16:22
sparky: I'm trying to picture a periscope of sorts...............help me out here - what am i missing? If you look straight into a tube, the end of which has a mirror at 45 degrees, and it looks into a tube at right angles to the original tube, would'nt that give you a 90 degree view?

480sparky
26-Dec-2015, 16:26
A periscope consists of two mirrors. I only want to use one.

A periscope uses a tube because it needs to keep out water. I'm not shooting underwater, so a tube isn't needed. I only need the mirror to fill the field of view.

Drew Bedo
26-Dec-2015, 16:32
Stephen T.:


NO. The firirst mirror at 45 bends the light path through a right angle. So with the camera level and the axes of the lens parallel to the ground, a 45 degree mirror in front of the lens will show an image of the sailing.

The principle involved is often stated as, "The angle of reflection equals the angle of incidence". Light from the ceiling hits the mirror at 45 and leaves it at another 45. This sadds up to 90 degrees, or a right angle.

Did I confuse or clarify?

Jac@stafford.net
26-Dec-2015, 16:43
Take the easy route first. Google Camera Right Angle Mirror.
I don't know what diameter your lens has, but something along the line might be available.

There are some here. (http://www.bhphotovideo.com/c/search?Ntt=Right+Angle+Mirror&N=0&InitialSearch=yes&sts=ma&Top+Nav-Search=)

redshift
27-Dec-2015, 06:02
There is a Sinar front surface mirror for sale on the bay, just listed. No, it's not mine!

Drew Bedo
27-Dec-2015, 06:11
I think the first two will need a longer focal length than the OP wants to use and the rest are for the eyepiece end of telescopes.

It may be that the OP needs a larger front surface mirror mounted separately from the lens; cumbersome to be sure, but the final image is what is important. The old (very old now) large screen projection TV sets had a front surface Mirror that was several square feet. The SX-70 system Polaroids have a front surface mirror that might work for an external set up. The Polaroid MP-4 copy cameras had a right angle viewer that could be salvaged and used. The mirror in some other 4x5 right angle viewer could be salvaged and rigged.

If the need is imperative the possabilities are there. It may be that rigging a mirror based appliance is more troublesome than shooting straight up with a lightweight wide angle camera such as a TravelWide. Focal lengths available are 65mm and 90mm. How wide do you need to shoot?

Drew Bedo
27-Dec-2015, 06:35
A laser reflector ~6x6 inches, mounted on an adjustable stand

http://www.ebay.com/itm/6-ADJUSTABLE-LASER-LIGHT-SHOW-BOUNCE-MIRRORS-mirror-front-surface-optics-fence-/201485094907?hash=item2ee9728ffb:g:bakAAOSwqu9VQSl7

Seriously; take a look . . .this could be perfict.

480sparky
27-Dec-2015, 07:52
FINDING a suitable mirror is not the issue.

HOW TO MOUNT IT is what I'm inquiring about.





Take the easy route first. Google Camera Right Angle Mirror.
I don't know what diameter your lens has, but something along the line might be available.

There are some here. (http://www.bhphotovideo.com/c/search?Ntt=Right+Angle+Mirror&N=0&InitialSearch=yes&sts=ma&Top+Nav-Search=)

See post #10...........

Jac@stafford.net
27-Dec-2015, 08:22
FINDING a suitable mirror is not the issue.
HOW TO MOUNT IT is what I'm inquiring about.

How does one attach anything to the front of the lens? If you would please tell us what lens(es) you are working with, and hopefully some measured dimensions such as front outside diameter, what size screw-in filter it can use (if any), whether it can use a compendium (because a part of it might be used), and so forth then we do not have guess just what issues you have.

480sparky
27-Dec-2015, 08:41
Nikkor-W 65/4
Nikkor-SW 90/8
Nikkor-SW 150/5.6
Caltar-S II 210/5.6
I have adapter ring for all to use 77mm filters.

Jac@stafford.net
27-Dec-2015, 09:43
Nikkor-W 65/4
Nikkor-SW 90/8
Nikkor-SW 150/5.6
Caltar-S II 210/5.6
I have adapter ring for all to use 77mm filters.

You have have the adapter for all - that is excellent!

Later I will be at the bench where I can measure a copy camera's 90 surface mirror adapter. The 77mm (3") opening is probably an issue in finding a ready-made. Also having a mirror box large enough for the widest angle is important. Perhaps someone can tell us what the angle of view is for the 65mm (I don't use one.)

That said, if this were my project I would probably make (or have one made) - a right-angle mirror box of lightweight, reinforced wood. 45 angles are a natural to cut. Now I realize the following adds a lot to the setup, but it was intended for odd add-ons and it is highly adjustable. It was made for Celestron telescopes, is rigid and lightweight enough. (Astronomy fans have good resources.)

Shown below, the adapter stand on tripod. The leftmost part is vertically adjustable and the rest of the stand accommodates many configurations; in this case a 4x5 view (Sinar Alpina). The black part supporting the lens is wood and anything similar can be made to be a box. (The rest is steel and aluminum.)

144034

(Man, do I have a lot of odd stuff!)

480sparky
27-Dec-2015, 10:20
The 65mm, at f/16, covers 105.

Jac@stafford.net
27-Dec-2015, 19:13
Later I will be at the bench where I can measure a copy camera's 90 surface mirror adapter.

I checked it and it won't work. So, it's off to you or anyone else who can help. I'd make a box if I wanted such.
.

Drew Bedo
27-Dec-2015, 19:36
FINDING a suitable mirror is not the issue.

HOW TO MOUNT IT is what I'm inquiring about.

See post #10...........


The link I provided shows a mirror with a support stand that nay be positioned as needed.

this would not be attached to the lens, but placed where you need it . The camera is placed to catch the reflection.

In practice; the mirror is set under the target at a 45 degree angle, while the camera is aimed at the mirror horizontally. The view on the ground glass will be the ceiling directly above the mirror.

480sparky
27-Dec-2015, 20:01
The link I provided shows a mirror with a support stand that nay be positioned as needed.

this would not be attached to the lens, but placed where you need it . The camera is placed to catch the reflection.

In practice; the mirror is set under the target at a 45 degree angle, while the camera is aimed at the mirror horizontally. The view on the ground glass will be the ceiling directly above the mirror.

That's for longer lenses. I'm sure even my 210mm would have vignetting issues.

Jac@stafford.net
27-Dec-2015, 20:30
That's for longer lenses. I'm sure even my 210mm would have vignetting issues.

Members have given you a lot of leads. Perhaps it is time now to think creatively and come up with your own solution.
.

480sparky
27-Dec-2015, 20:33
Members have given you a lot of leads. Perhaps it is time now to think creatively and come up with your own solution.
.

Well, so far I've got several comments about using quality glass (obvious), two posts suggesting a Spiratone thingy that is made for long lenses, and making an entire custom camera.

Still no suggestions on how anyone has done this.

Jac@stafford.net
27-Dec-2015, 20:37
Well, so far I've got several comments about using quality glass (obvious), two posts suggesting a Spiratone thingy that is made for long lenses, and making an entire custom camera.

Still no suggestions on how anyone has done this.

You have not been paying attention, or are being intentionally obtuse. Welcome to the ignore file.
.

480sparky
27-Dec-2015, 20:43
You have not been paying attention, or are being intentionally obtuse. Welcome to the ignore file.
.

Would you care to explain the photo you posted? Where is the mirror? How does this device attach to the camera/lens? Why does the device have a lens on it when my camera already has one?

Jim C.
27-Dec-2015, 21:56
Jac's picture is a bit hard to decipher, but he does say it has a camera mounted on it and what he's suggesting
and what Drew said too is to have a rig that will hold a mirror that you can place in front of the camera, not on the lens.
You're going to have to make it, build a whole custom rig or just some friction hinges attached to the
frame that holds your mirror.
None of you lenses will care, since you're focusing past the mirrors actual surface. ( hope this doesn't confuse )

You never mentioned what kind of camera you're shooting with, studio view cams will be more involved in
making a rig, self casing field cameras would be easiest.

480sparky
27-Dec-2015, 22:22
This will be for a Shen Hao HZX 45 IIA. If it was a monorail, it would be an easy do, especially if the rail is round. But this is a flatbed field camera.

Jac@stafford.net
28-Dec-2015, 00:41
The simplest might be to forget about the mirror in front of the lens. Point the camera straight up. A decent 3 axis head will do that. Then use a 90 viewer over the ground glass to make viewing more comfortable. (there is one for your model)

////////// moving on, or backwards \\\\\\\\\\\\

In my picture the point was to show that there is a movable platform that can be placed in front of the lens. In my set up it was being used to support the lens. The camera can be placed further back from the front platform which can be raised and lowered.

Upon that platform a mirror can be mounted. For example, a mirror can be mounted flat to a something resembling a Ries mount (http://69.195.124.213/~riestrip/wp-content/uploads/2014/11/DSC_0083.jpg)that can screw onto on the adjustable platform, tilted 45 and locked in place. (Just back off the center screw and tape or glue the mirror on.) I'm not about to make the setup just to illustrate what should be obvious.

Here is a crappy photoshop hack.

144068

It might be interesting to use the mirror off 45 as some kind of tilt, too.

Jim C.
28-Dec-2015, 01:16
This will be for a Shen Hao HZX 45 IIA. If it was a monorail, it would be an easy do, especially if the rail is round. But this is a flatbed field camera.

A flat bed is the easiest to rig, two boards, one long, one short, a pair of friction hinges, mount the mirror on the short board
spring clamp it to the flat bed.

Jac@stafford.net
28-Dec-2015, 01:21
Here is another version of a platform. Again, like the one I showed the front mount has an adjustable height.

144069

Jim C's idea would work, too. Keep it simple. :)