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Lenses

Discussion in 'General Equipment Chat & Advice' started by albini13, Sep 16, 2002.

  1. Benchista

    Benchista Which Tyler

    There are two versions - DEP mode on the better cameras, A-DEP on the others.
    DEP works exactly like that, and on some (but not all) models it can be "shifted" (i.e. you can adjust the aperture/shutter speed combination chosen by the camera). DEP is extremely useful for landscapes and portraits (as it's also very useful for limiting depth of field) and works remarkably well. A-DEP relies on the items required in focus being covered by the various focus sensors of the camera, and is not as good, but with a little effort can work very well. One camera, the EOS 10, had both options.

    Nick BSRIPN
     
  2. Larry Shone

    Larry Shone Well-Known Member

    not the same as hyperfocal distance is it.i was expecting some exciting revelation!
    Well, I'm off to use the colleges computers to do some swatting now.

    See yers later.


    There is nothing worse than a brilliant image of a fuzzy concept.

    - Ansel Adams
     
  3. Benchista

    Benchista Which Tyler

    Granted A-DEP isn't as easy as DEP in terms of making the most of it, but with a little effort it works just as well on the EOS 300 - it's just a matter of ensuring what you want in focus is covered by the focus sensors, then re-framing afterwards.

    Nick BSRIPN
     
  4. Benchista

    Benchista Which Tyler

    Strictly speaking, no it's not, but it is if you select a point at infinity and one right at the end of your nose, as it were. In truth, it's actually more useful than a true hyperfocal setting.
    Forgot to mention that there was a Hyperfocal card for some Dynaxes when they used the add-on card system - don't know which ones accepted it, though.

    Nick BSRIPN
     
  5. Reading

    Reading Well-Known Member

    Isnt DEP an EXPOSURE mode rather and anything to do with where the camera focusses? I dont quite understand your explanation, but it sounds suspiciously like you focus on a point and the camera ensures other points are covered by adequate DOF, rather than the camera choosing the point of focus at the hyperfocal distance. I could be (and usually am) wrong though.

    Having just read your other reply I think I am wrong. It is just the canon site which is misleading by calling it an exposure mode.
     
  6. Benchista

    Benchista Which Tyler

    It's set as an exposure mode, yes. But it goes further than that.
    In DEP mode, you focus on the near point, then the far point. The camera then calculated a focus point and aperture to give you the appropriate depth of field. Set these two points as the closest possible focus distance and infinity, and it'll set the true hyperfocal distance for the lens. It's an exposure mode in that it also sets an appropriate shutter speed. In effect, it does what any half-competant photographer can do with manual focus lenses and a rangefinder or SLR armed with engravings or a set of tables. But it does it well and quickly. Personally, I wouldn't buy an AF SLR without it, but other people have other requirements!

    Nick BSRIPN
     
  7. Reading

    Reading Well-Known Member

    Agreed, sounds very good - can I take one in a K mount please? I use the engravings on the lens (and wouldnt buy a lens without them ideally), but their pinpoint accuracy is questionable, so I always have to allow for a bit of extra DOF.
     
  8. albini13

    albini13 Well-Known Member

    I`m stunned. Can`t really tell if my question has been answered or not but thanks anyway. I never use the depth of field preview button or the A Depth facility, i just guess mainly. Sounds like i`m a long way behind you guys as far as my photography goes. Like i said in an earlier thread, i use autofocus because my eyes aren`t great. I think i need to read up more. Cheers folks.
     
  9. TimF

    TimF With as stony a stare as ever Lord Reith could hav

    …I never use the depth of field preview button…

    Truth be told Gavin, neither do I - well not much anyway. If you tend to use one particular focal length a lot, I think you develop a feel for what aperture will be needed for a given DoF effect (that's probably even more the case with a Leica where there's no through lens view). I tend to use f/5.6 or f/8 mostly, or wider than that.



    Tim BSRIPN
     
  10. Benchista

    Benchista Which Tyler

    I don't really disagree - where the Canon system really comes into its own is with zooms.

    Nick BSRIPN
     
  11. Reading

    Reading Well-Known Member

    Sorry, to answer your question...

    The sigma is not (I think) a true macro lens. They only call it that because wide angles intrinsically focus pretty close, and their design possibly goes close enough for them to get away with calling it macro.

    Whilst I dont know the Canon lens, all wide angles will likely focus pretty close and do pretty much as good a job as the Sigma in this respect.

    The Sigma 24 F2.8 is exceptionally well regarded optically for an older Sigma lens. Alot of their old stuff was not too well received, but apart from a susceptibility to flare and poor build, the 24 is a cracker.

    The Canon should be built a lot better and will probably be every bit as good optically.

    Also, bear in mind that sigma also now do a 24mm F1.8 which could well be as cheap as the canon and has USM so will not have the noise problems you describe. It is also very much better built that the one you have, but is much bigger due to the wider aperture.

    In terms of having both, well the Sigma sells for about £60-£80 second hand in shops, so you would expect to get possibly as little as £40-£50 for it, so it would not be worth selling. Keep it as a lightweight backup, and a cheapie if you go anywhere you dont want to risk damaging your much more expensive lens.
     
  12. albini13

    albini13 Well-Known Member

    What is your opinion of the Sigma 20mm 1.8 ? This goes for about £350 new. Is it worth the money and what site can i look at to see its test results ?
     
  13. TimF

    TimF With as stony a stare as ever Lord Reith could hav

    It got a good write up in AP, but I hear that others weren't so complimentary, saying that it vignettes quite a bit. If you have a good dealer see whether they'll let you borrow one to run a film or two through it. (you may have to leave the entire cost as deposit of course)

    Tim BSRIPN
     
  14. Benchista

    Benchista Which Tyler

    http://www.photozone.de user reviews rate it as Very Good; however, their AF SLR lens test guide, "averaged lens ratings based on tests from various photo magazines from all over the planet" rates it as poor (by some way the worst 20mm tested). Do you believe users or testers? I don't know.

    Nick BSRIPN
     
  15. gordonblue

    gordonblue Well-Known Member

    I've got the Sigma 20mm 1.8 and I'd recommend it. It's not comparable to 'pro' lenses in terms of quality, but is fine for amateur use. Bought it for a trip to Vancouver & Seattle and didn't regret it. You can get it for under £300 if you shop around. I paid £270.

    G.
     
  16. Done_rundleCams

    Done_rundleCams AP Forum Ambassador to Canada

    Re: Lenses / albini / tim

    " you have a good dealer see whether they'll let you borrow one to run a film or two through it. (you may have to leave the entire cost as deposit of course"

    Tim,

    Not if you bring your camera with you. All you have to do is stick the lens
    on and do some shooting inside the shop which is a good way to check the
    lens wide-open and then do some shots outside the shop. Then, if the
    shop has a Photofinishing lab just drop off the film and wait for the results.

    Gavin,

    Please see above message.................or get your Sigma rep to loan you
    the lens for a weekend or even a lunch hour. Oh, and expect to spend nearly as
    much for a for a protection filter as the lens./img/wwwthreads/wink.gif

    /img/wwwthreads/smile.gif

    Jack

    It's amazing what one can do when one doesn't know what one is doing!/img/wwwthreads/wink.gif
     
  17. Reading

    Reading Well-Known Member

    Re: Lenses / albini / tim

    When I was looking at the Sigma 70-200 F2.0, my local Jessops only had it in Nikon mount so I had to try it on a Nikon body. The manager refused to let me take any pictures as he said the stuff would then be 'used'. It was OK to put it on a body and practice focussing on objects and firing the shutter etc, but if he would not let me put a film in it!

    LCE got me a loaner of the lens from Sigma and let me go outside and walk around shooting with it.
     
  18. Benchista

    Benchista Which Tyler

    Re: Lenses / albini / tim

    Why am I not surprised about both experiences!

    Nick BSRIPN
     
  19. albini13

    albini13 Well-Known Member

    Re: Lenses / albini / tim

    So if the Sigma has had bad reviews the only thing for me to do is test it out and see. What would you all consider to be a good buy (wide angel lens wise). I want to go as wide as poss without getting a fish eye effect. What lenses rate highly ?
     
  20. Larry Shone

    Larry Shone Well-Known Member

    neither will be true macro lenses unless reversed.and that causes all sorts of problems with wideangles!

    There is nothing worse than a brilliant image of a fuzzy concept.

    - Ansel Adams
     

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