test test,,,sorry
Στις 7:59 μ.μ. Δευτέρα, 22 Φεβρουαρίου 2016, ο/η Herschel Mair <herschphoto@xxxxxxxxx> έγραψε:
It's not the lens that gives depth of field. It's the magnification. and from the same camera position the magnification at any given distance in proportional to the focal length 1/o +1/i =1/f... M = i:o If however you change the optical bench position of the camera so that the magnification is the same, then the depth of field will also be the same at that focal distance. But if you only change the lens and leave everything else the same then the depth of filed will be proportional to the focal length.
On Mon, Feb 22, 2016 at 9:19 AM Randy Little <randyslittle@xxxxxxxxx> wrote:
This is a brief bit from that article if you don't want to read the entire thing. It's good though if you have the time. A bit more in depth in regard to Herschel's statement.WIDE ANGLE LENSES & DEPTH OF FIELD
Note that nowhere in this page is it mentioned that a wide angle lens has a greater depth of field. Unfortunately, this is another common misconception. If you are magnifying your subject by the same amount (meaning that they fill the image frame by the same proportion), then a wide angle lens will give the same* depth of field as a telephoto lens.*Technical Note: for situations of extreme magnification, the depth of field may differ by a small amount. However, this is an extreme case and is not relevant for the uses discussed in this page. See the tutorial on depth of field for a more detailed discussion of this topic.The reason that wide angle lenses get the reputation of improving depth of field is not because of any inherent property with the lens itself. It's because of how they're most often used. People rarely get close enough to their subject to have them fill the same amount of the frame with a wide angle lens as they do with lenses that have narrower angles of view.On Mon, Feb 22, 2016 at 11:04 AM, Randy Little <randyslittle@xxxxxxxxx> wrote:Best least techy article I could find.
http://www.cambridgeincolour.com/tutorials/wide-angle-lenses.htmOn Sun, Feb 21, 2016 at 7:29 AM, Herschel Mair <herschphoto@xxxxxxxxx> wrote:DOF is related to magnification so it diminishes as your image size increases. From the same camera position it will decrease as focal length increases.On Sun, Feb 21, 2016, 00:26 Kostas Papakotas <clenchedteethphotography@xxxxxxxx> wrote:wow! i never thought such a big discussion would happen!And while I am still trying to absorb all this a new question sprang in mind.I guess Depth of Field has nothing to do with the issue and perspective distortion.Cos if the tester compensated with aperture to get the same DOF between shots, all cropped frames would be exactly like the telephoto one.And if he didn't, all (cropped) versions would just have a different DOF. (and would maintain the same perspective)Στις 9:36 μ.μ. Παρασκευή, 19 Φεβρουαρίου 2016, ο/η Randy Little <randyslittle@xxxxxxxxx> έγραψε:
Knowing and not knowing are not the same as people teaching it wrong.On Fri, Feb 19, 2016 at 2:21 PM, Herschel Mair <herschphoto@xxxxxxxxx> wrote:I know that from your perspective, you're absolutely right and I thought the same way for a long time... Yes, for the technical applications you speak of, I agree. While I was working with large format cameras it had some application... But I will probably never have to make a motion picture matte on an 8x10 camera... When I look back at all the technical education I've had,(I studied photography as part of the Printing and Commercial Reproduction Department at a technical college) its significance pales when compared to the the lessons I've had in seeing. I know if I need flattened spatiality, I need to get away from the subject and then use a lens that crops the shot to what I want. (I don't own a zoom any more) If I can't fit it in the frame I use a wider lens. or move back a little more... I don't need to know the physics of it or anything more than I could learn in a painting class on perspective.But that's just me and I'm never satisfied with my work.On Fri, Feb 19, 2016 at 11:59 AM Randy Little <randyslittle@xxxxxxxxx> wrote:BECAUSE you teach them how the lens actually works. A normal photographic lens doesn't compress space. Period it doesn't. You moving it does. The only reason you couldn't' use a wider lens has zero to do with lens compression. Its has to do with what you want the image to be in relation to a whole bunch of other stuff spatially and the ANGLE OF VIEW of the lens. That has just literally zero to do with Lenses compress space. Spatial relationships compress or expand space visually. I could teach people that Sun goes around the earth cause it looks that way, but it's still wrong. It's crazy to say don't teach something because you don't think it's used. I don't need to know circles of confusion I only need to know that f1.4 means less area is in focus and f64 means lots is in focus. I for sure didn't need to learn to disguise artist by their brush stroke styles. (yes I did have to in history of American painting)
I can think of a lot of cases where your last line is pretty use full. Lack of a macro lens, photographic survey, barriers to getting close to a subject. Shooting still plates for matte paintings that have to match Film plates but you only have the right focal length and not the right camera. (super35 vs ff or larger) Not every situation works out as an ideal situation, knowing how things actually work is kind of handy.On Fri, Feb 19, 2016 at 1:21 PM, Herschel Mair <herschphoto@xxxxxxxxx> wrote:Randy, the question is not whether you could do all that (And indeed, technically, you could) but WOULD you do that? ... for a $300.00 jewelry shoot?And let me put it this way.... I did an on-location car shoot for Mazda in the 80s. On 10X8 Sinar with a 980mm Schneider lens (Very little DOF at f:32) (Needed 3 tripods for film, middle standard and lens) How could I have done THAT without the long lens? And still give the client the 10x8 tranny?Why teach stuff to people if they're never going to use it... New course : "How to use a 100MP Phase one cropped down to 24X36mm"On Fri, Feb 19, 2016 at 9:39 AM Randy Little <randyslittle@xxxxxxxxx> wrote:but technically you could get the 100MP phase one and crop it and get the same result as a 25MP sensor and shoot a wide lens on the 100MP. I could technically shoot with a 90mm on my 8x10 (SUPER WIDE)and crop that shot to have the same exact result if the camera is in the same exact spot as a 35mm camera with whatever lens for the most part. The only difference is angle of view. It would be the same in all other aspects. The only time it wouldn't is if there is lens distortion. It would be a total pain to shoot like that and not at all practical but the result IS the same. Once you move to compensate for the focal length then you are changing all kinds of geometric relationships which is the only reason it its different. Right? You change Focal distance, actual distance relationships and whatever. All that is true and all that is real world. That doesn't change the FACT that any rectilinear lens on a camera at the same position produces that exact same result if you crop them to show the same thing. Lenses do not compress space. Spacial relationships of camera to subject distance and focal distance do. Which is what Herschel is doing in his example. The lens isn't compressing space Herschel is by changing the relationship of the camera to the subject.On Fri, Feb 19, 2016 at 9:48 AM, Herschel Mair <herschphoto@xxxxxxxxx> wrote:TECHNICALLY it's a myth... CREATIVELY, a longer lens allows you to get further away from your subject and by so doing gives you a flatter perspective. Why over-think this? If I want to shoot a jewelry shot on a model, I use the 300mm f:2.8 because it allows me to get the flattened background and it allows me to get tiny DOF.... I don't use the 24mm and then crop it... There's no way for me to do that pic unless I have that lens... Technical perspectives are only as useful as they support the creative eye. Beyond that they are for technicians, not photographersOn Fri, Feb 19, 2016 at 4:24 AM John Gulliver <j.gulliver@xxxxxxxxxx> wrote:I agree about Feininger Snr. and his book. He wrote well. I know this picture too, for which he invented a tripod with an extra leg to support not only the camera but the long lens to reduce possible vibration.
Sent from my iPhoneAndreas Feininger was my first photo teacher by way of one of his books ... many of his books were slightly modified versions of the first one. I say this with a twinkle in my eye!-------- Original Message --------
Subject: Re: Debunking the telephoto lens myth?
From: Jan Faul <jan@xxxxxxxxxxx>
Date: Thu, February 18, 2016 4:40 pm
To: "PHOTOFORUM@xxxxxxxxxxxxx" <photoforum@xxxxxxxxxxxxx>
My first purchase of a photo book was one by Andrea Feininger in which he showed the use of an extremely long telephoto lens from out in NJ looking towards Manhattan and it compresses NJ into a series of hills and sort of pasted the Empire State Building in at the back. Every time I drove to NYC I thought of his work with the Pulaski Skyway and the flattening of NJ.
