Dan Diaconu M

With you (and Karl) at work, the picture looking good is no surprise David. What lake was that in the scene? Was the whole picture in or around Vancouver (or just parts). Cheers, Dan

No, it does not matter all that much, just a little bit. I choose a focal by "need" (space available, action, meaning of the dialog, etc) but I would like to have some sort of reference point. Agree. I agree again. I agree most people will hardly notice the difference, but if pointed out what to look for, they will order them from wide to tight. The question I asked was related to smaller formats where the "diagonal" doesn't produce the "normal. In my previous post I mentioned two different focal lengths for the same format (13.8X20.7mm). The "normal" by frame diagonal turns to be a 25mm. That's a long way to go to the 70 that matches the eye view. I don't fuss over 5mm (more or less) here David. Generally and about doest cut it either. We have almost three times the difference. I suppose you have an SLR (film or digital) handy (a digital would actually be better). What would you call "normal" between a 25 and a 70? Thanks for contribution.

I have supported for years the following definition of the "normal" lens: http://en.wikipedia.org/wiki/Normal_lens without even thinking about it or trying to check it out. It all seemed so....well... logical and in place and used to it (as is) for soooooo many years..................... Yet, today I bothered to look trough the viewfinder and discover something doesn't add up. If "normal" means 1"as seen by the naked eye" but at the same time 2"equal to the diagonal of the format", well.... Huston, we have a problem! The two do not seem to go together. One of the two must go (imo). OMG!!!!!!!!! a landslide. In practical terms: left eye open, right eye in the viewfinder of an SD10, I panned the camera left/right and found 70 (from a 55-200) as the focal length where the two images were seamlessly blending with each other. In other words, I captured an image "as seen by the naked eye" with the zoom set at 70. "As seen by the naked eye" means the same perspective and the same size ratio between the elements (buildings in this case) in the frame. Although, the frame is much smaller (13.8X20.7 mm) than "normal" SLR (24X36mm), that section photographed looks "normal" (imo) reproduction of what I can SEE. ( I captured another image at 25mm (18-50) and compared the two. The latter looks like a wide angle to me. Two prints on the table: which one is "normal"? Well than, where does "equal to diagonal of the format" fits in the definition than? If I may call your attention the "double standard" definition in wiki where "normal" is twice the diagonal for motion picture lenses (accounting for viewing distance they say) Scaling down the projection distance and screen size to a comparable "picture on the table", shouldn't the rule be the same? I urge you to set aside any dogma and check it out and see for yourself. What is "normal" for you? Or.... how do you define "normal" ? Cheers, Dan Diaconu PS. I did the same test as above with a SLR (Nikon) 24X36mm and discovered that 55mm produced an image identical with naked eye. Not 50, not 45 and not the theoretical 43.26.

quote: The only focus reference that is worth anything is one that doesn't move. end quote. more sound advice here: http://www.cinematography.net/edited-pages/FOCUSING.HTM

Here is what I would try: find a lens (acting as a diopter) and glue it centered on a UV filter on the camera lens. It should be roughly the diameter of the image you want to see (about 1/4???? of the filter??) I know it takes some experimenting with different focal lengths but it provide you with just the shoot you need. You could also use it in combination with another lens (mimicking the scope) You know better how much effort is worth the shoot. Good luck anyway. Dan Diaconu

Although answered already, for the "why" part is because any smaller section of the lens is closer to the design than the whole lens (hence the high price of fast lenses/primes and the less expensive digital zooms starting at 4/5.6). But I have another question: from a practical point; how does one measure the confusion? Some people like to add a personal touch to their images http://fc01.deviantart.com/fs27/i/2008/107...by_pixel_ah.jpg and those are far from circles. Daytime images (without lights) still show a fair amount of bokeh (confusion) in their natural shape (not necessarily circles) Is there an apparatus (caliper or something) to measure the confusion?(charts aside) How do you do it? The confusion grows with the projected screen size and distance (not only lens, aperture and originating format). Help, I am diffused.

Of course but only if it got burned (exposed :rolleyes:) early in life. (Chaplin, et all)

No no no no NO. You got it all wrong friend. That's for a different kind of animal. May I suggest "lens and shutter"? (and if that don't work, try claw and registration pin although sounds like grab and rape) PS. Don't use cannons to kill mosquitoes. (flowers'n candy 4 film. Sheesh.....)

So.... you start a thread only to let us know you're staying home? :blink:

why carpet the whole world when you can put some sleepers on? ;)

They had about 100 years to fine tune the movement from the original http://www.speedace.info/sewing_machines/s...ia_maxfield.jpg to the new application. No rotating mirror? Machine gun like sound? No video tap and you call that "worked properly"? Did the hand cranked models before it worked properly?Yes? No? WW1 footage, Modern times, City lights....good? no good? 535 works properly (now). Side it with D21. It's like an M5 versus Aptera. "Properly" without a time address doesn't mean much. Work in progress (imo) best defines all we do (I got your point too).

I was able to focus on anything the light touches using two video cameras mounted on the sides of the mate box. (those in the field for some time might remember). Google 6160607 for details on the apparatus. That was moving camera/targets, wide open, constant or random moves. Constant being dolly-in or out and random being swinging target (think of a pendulum) combined with dolly-in or out. In short, it is possible to keep anything in focus each and every time (first take included) without rehearsals. On coc, personal taste or confidence using charts, no comment. Cheers, Dan. PS. David, if you are curious to try the device, it is closer to you than you think. PM me if interested (beer)

Playback the music loud and clear (CD?) and shoot the video. Lay down two audio tracks in post: 1-original CD and 2-the recording of it with picture. Sync them up. Mute the second sound track. Playback picture with original CD track. I hope this helps. Cheers, Dan

Thanks for correcting the definition. Some set primes include 32, others...35. Some sets have a 40 (aside from 50) and yes, the lens that doesn't change the "normal" perspective is the "normal". 32 is "more normal" :lol: (mwuaaah) than 35 is. Human vision seems to be the same for all (if you want to be included or excluded) http://webvision.med.utah.edu/Facts.html and I must confess: I do not know how many of my cones are still working :blink: (hell... don't even know how many I had to begin with :lol: ). Cheers, Dan

A "normal" lens (for any given format) is the lens providing the same FOV as the naked eye. A "normal" lens (for any given format) is the focal lens that equals the diagonal of the format. I don't know if one can or how to "calculate" the FOV, but: 7.9967 (hence 8mm) is the "normal" for 1/2", as well as the 35 is "normal" for motion picture and "50" is "normal" in still photography film. Now, the FOV of a "50" is "normal" when used on a 24/36mm frame and the same lens gives you the FOV of an 85 when used on a motion picture camera (due to the crop factor) 35 lens is "normal" on an ARRI/Panavision and "wide" on a film-still Nikon, Canon, Minolta, etc. I hope this helps. Cheers, Dan Diaconu.