RE: [pinhole-discussion] math
Pinholes are like snowflakes, but microscopes are notoriously accurate, and my math is better than some think. I know how big my pinhole is, I know what my effective aperture is. What done it is knowing one's materials and equipment, and using that knowledge as a means, not an end. We can spend all day quibbling about who is right and who is wrong, but in the end what we ought to be doing is gazing through our pinholes and discovering new worlds. --Original Message-- From: "sky...@earthlink.net" To: pinhole-discussion@p at ??? Sent: November 24, 2000 6:03:53 AM GMT Subject: [pinhole-discussion] math pinholes are not alike just like snow flakes so easy to mess up any bodys assumptions nothing is exact the hole done it p.s. the way to darkin the hole is to take a small piece of rubber lite it with a match let the soot do the job has no density acts as a perfect assorber of stray light intering the hole no reflections other chemical, paint or whatever has density and will act as a reflector of light several applications of soot willcreate a passage for light with much better results handle with care rubs off ___ Pinhole-Discussion mailing list Pinhole-Discussion@p at ??? unsubscribe or change your account at http://www.p at ???/discussion/
Re: [pinhole-discussion] READ THIS ONE- Studio Photography
Tom, What works for you may very well differ from what works for me. I know that my system works because I use it constantly to produce exceptional negatives and polaroids. In many cases I scan my polaroids and work from the scans. If you want to sit in the studio all day and fire off strobes, that is your business. I was merely sharing my experiences, which have been very positive, with someone who asked a question. You can sit there and tell me that for my exposures I need to fire my strobes 40 times, but I know from experience, that 5 or 10 is quite sufficient on both polaroid and film. Right now I looking at a correctly exposed type 52 polaroid, that according to your "math" would have required 63 "pops" but actually only took 10. Mathematically you may be correct, but experience, and my cork board covered with polaroids tells me that my system works just fine. This is a good list serve because ideas get thrown around and people enthusiastically share information. However, it gets messy when arguments begin and it becomes a war over who is right and who is wrong. We are both right. This is an art, and in art there is no benchmark, but only personal expression. My techniques work for the images that I work to achieve. Do what works for you and don't attack me for relating what I've found to work. Perhaps I was hasty in saying that doubling your "pops" to add a stop is nonsense. In the future I will not make judgments about other people's opinions. Levi On Mon, 20 Nov 2000 17:14:34 -0800 Tom Ferguson writes: > > From: Levi Brown > > Subject: [pinhole-discussion] READ THIS ONE- Studio Photography > > > > Andrew, > > I've been doing this for several years now... here is what you > do. > > First determine the effective aperture of your camera. For my 4x5 > mine > > is about F-256 and for my converted Hasselblad it is about F-140. > Get > > yourself a flash meter and get your strobes close to your > subject. > > Ideally if you can get your meter to read F-45 you are doing good. > This > > whole bit about doubling your number of flashes to add an extra > stop is > > nonsense. Everytime that you flash the strobes you add an extra > stop of > > light. Lets say that I set up my lights and get a meter reading > of F-45. > > Lets count: F-45, F-60, F-90, F-128 That equals 4. So to get > > sufficient exposure you need to pop your flash 4 times. Just to > be on > > the safe side do it 5 to add a little extra density and account > for > > reciprocity. It really is that simple. With my Hasselblad my > exposure > > times are about 4 pops of the flash and with my 4x5 they run > around 9. > > I'm sorry, but as someone who uses multiple flash pops for both > pinhole and > lens work, this is simply WRONG. F45 to F128 needs AT LEAST 8 > times as > many "pops". Lets count: F45 to F64 is one stop (X2), F64 to F90 is > another > stop (2X2=4), F90 to F128 is another stop (4x2=8). I say "AT LEAST" > because > reciprocity (on the other end of the spectrum from pinhole, flashes > can be > too short an exposure) can increase the number of "pops" needed. > > My best guess is that Levi is using Neg film, as surviving on it's > wonderfully forgiving exposure latitude :-) > > Try this with E-6 slide film or polaroid, and you'll see the truth. > > > > > Another trick, if you are shooting black and white, is to use Tmax > 400 > > speed film. Tmax has significantly less reciprocity failure than > other > > black and white films. I've noticed that I get better negative > density > > with Tmax than with any other black and white film. > > Agreed! It is a nice film isn't it. The 100 speed T-Max is even > better for > reciprocity. > > >SNIP> > > -- > Tom Ferguson > http://www.ferguson-photo-design.com > > > ___ > Pinhole-Discussion mailing list > Pinhole-Discussion@p at ??? > unsubscribe or change your account at > http://www.p at ???/discussion/ >
[pinhole-discussion] READ THIS ONE- Studio Photography
Andrew, I've been doing this for several years now... here is what you do. First determine the effective aperture of your camera. For my 4x5 mine is about F-256 and for my converted Hasselblad it is about F-140. Get yourself a flash meter and get your strobes close to your subject. Ideally if you can get your meter to read F-45 you are doing good. This whole bit about doubling your number of flashes to add an extra stop is nonsense. Everytime that you flash the strobes you add an extra stop of light. Lets say that I set up my lights and get a meter reading of F-45. Lets count: F-45, F-60, F-90, F-128 That equals 4. So to get sufficient exposure you need to pop your flash 4 times. Just to be on the safe side do it 5 to add a little extra density and account for reciprocity. It really is that simple. With my Hasselblad my exposure times are about 4 pops of the flash and with my 4x5 they run around 9. Another trick, if you are shooting black and white, is to use Tmax 400 speed film. Tmax has significantly less reciprocity failure than other black and white films. I've noticed that I get better negative density with Tmax than with any other black and white film. To pop the strobes, just push the button on the flash meter. If you don't have a free hand, you can fire the strobes by putting a peice of metal (like a paper clip) in direct contact with the sync cord. I rigged up a firing mechanism using two clothes pins, a paper clip and some gaff tape. (if you are interested in gaff tape, check the messages over the past couple of weeks!) What you do is tape everything together so that when you squeeze the clothes pin it moves the paper clip into direct contact with the inside of the sync cord. If you rig it just right, you can fire your strobes by merely tapping it with your foot. Kinda hard to explain... you will just have to give it a try. Levi
[pinhole-discussion] Silver materials
I'm looking for some silver sheet material that is as small as .001" thick to as large as .003" thick. I'm tired of using brash shim stock and would like to make my lenses out of a more workable material. I have a couple of jewelry making catalogs that sell 34 gauge (.006") but I would like to find something that is possibly 36 or 38 gauge. (if that is possible) Anyway, let me know your thoughts on the matter. Levi Brown
Re: [pinhole-discussion] pinholes with hasselblad
Yesterday I made a pinhole "lens" for my Hasselblad and have run two roles of film through it with excellent success. Here is what I did... I found myself a peice of black matt board and cut a circle out of it that fit more or less into the front of my camera. I then put two layers of gaff tape (any thick tape will do) around the edges of the matt board to add thickness and account for iregularities in my scissor work. I poked a hole in the center, put the matt board on the camera and lined up the pinhole by staring through the back of the camera. I then taped the pinhole in place. My lens is made out of .001" brass shim stock with a hole that is .018" in diameter resulting in an effective aperture of F-160 (or somehwhere there abouts) The matt board plug pushes firmly into the front of the camera and works just fine. I've run two roles through with no light leaks and I've shot several polaroids as well. If you have a prism finder (somthing other than the waistlevel finder) in bright lighting conditons you can see through the pinhole to compose. Works very well on bright sunny days. For metering I use a Pentax Digital Spotmeter and meter for F-128 (which is as high as it goes) and then I just add a stop. In the studio I set my lights for F-64 and flash the strobes 4 times. So far every exposure has been right on... If you care to see the images let me know and I'll post them. ~Levi Brown On Thu, 9 Nov 2000 06:51:38 -0800 (PST) =?iso-8859-1?q?hannah=20smolenska?= writes: > hi there, > i'm interested in trying pinholes with medium format > film with a hasselblad, using 400 speed film. any > suggestions on exposure times? > thanks! > hannah
Re: [pinhole-discussion] pinhole and polaroid
Mark, I use type 52 Polaroid in studio for proofing purposes when I'm shooting portraits (usually self portraits) using strobes. It reduces my margin of error concerning my lighting scheme (studio lighting with pinhole is touchy) as well as tells me exactly where the camera is looking. One thing to keep in mind if you are using Polaroid merely to proof images is to set a cut of limit for yourself. I've found that if I shoot more than one or two Polaroids all my best images end up on the Polaroid and the images on the processed film ends up less than adequate in comparison. ~ Kerplop
