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#11 | |||
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VTphotog wrote:
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However, the purpose of my response was simply to help fofa understand the difference betweena 'Macro Lens' and a 'Close Up Lens', not to describe the nuances of what, exactly, constitutes 'Macro'. TCav wrote: Quote:
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#12 | ||
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TCav wrote:
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I don't want to spend the money on a macro lens (but the Sigma 150 macro is tempting) so I use extension tubes. I already own the Canon 100-400, and I find the tubes work well with that. I've heard that they can work well with the Canon 28-135 but I've never tried it. As a note to fofa, extension tubes trade distance focusing for close focusing (reducing the minimum focusing distance) so the subject looks bigger in the frame. They are cheaper than a macro lens, light and small (easy to carry) but they are only as good as the lens you put them on. Put them on a cheap lens and you'll have sharpness issues and larger f-stops will reduce quality even more. And you still have the small DOF problem. A solution to that problem is to increase the f-stop. But most non-macro lenses have a "quality curve" (as I put it) where they optically start to get better as you increase the f-stop, and then they peak and get worst. It's lens dependent as to where the peak is, but its normally around f/8 to f/11 (if you're lucky.) A dedicated macro lens, though, stays optically great way out into the f/18 range (or even further.) This is part of what you're paying for! And as said by others, you often shoot at f/18 or even more when doing macro. The downside to increasing the f-stop is you loose light. So you're shutter speed drops. You have two solutions to that problem. Stay steady (use a tripod) and hope your subject stays still (with controlled situations this isn't a problem, with wild animals or outdoors it is.) Or add light by artifically. An off-camera flash bracket can help. The previously mentioned ring lite is good. You can also use a macro twin-lite. A friend who does *stunning* macro work of bugs and lizards uses the twin-lite and does *not* recommend the ring lite. Another friend who does casual macro (but is generally a great photographer) loves the ring lite. The twin lite (yes, that is how cannon spells it) is here: http://www.usa.canon.com/consumer/co...p;modelid=7282 The ring lite is here: http://www.usa.canon.com/consumer/co...p;modelid=8127 You said something I want to correct/adjust: fofa wrote: Quote:
Ok, I'm nit-picking, but I felt I should mention it. Eric ps. All the comments about "optically better" and such are relative. I've regularly use over $10,000 of camera gear when I shoot (note, I'm not including what I've sold... just the value of the gear that I physically am using right now.) Clearly, my standards are high enough that I needed to spend that much money to get the quality of result that I wanted. This might *not* be true for you. You have to figure out what enables you to do what you want and what will achieve that at an acceptable quality and price. For example, I didn't spend $1,500 on a really great macro lens even though I could afford it (easily.) Because I just don't care enough about Macro to do it. Instead I own extension tubes and use them on a very good lens (Canon 100-400) and I'm happy enough with the results that I don't spend more money. You need to figure out that point for yourself. Luckily no one in this thread said "you should go buy X" because they really don't know what *your* standards are to say that. They can only say what they are happy with. Ok, I'll get off my soap box now. ![]() |
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#13 | ||
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eric s wrote:
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I quote from the Kenko DG Teleplus Extension Tube Set webpage: "There is light fall off when using any extension tube, sometimes the equivalent of 3 f-stops of light is lost when using multiple extension tubes together." The amount of light fall off depends on the lens (I think you can use extensions tubes with any lens, though there may be lenses that you don't want to use them on.), and, unlikewith teleconverters,is probably difficult or impossible to predict. Newer lenses, especially 'digital only' lenses are designed to project the image more perpendicularly to all pixels on the image sensor, whereas older lenses that were designed to work with filmmayproject the image at a more oblique angleat teh edges of the exposurebecause film could handle it. When the lens projects the image at an oblique angle, more of that light is lostinside of the camera body and the extension tubes, so less light gets to the image sensor. But with newer lenses, since the lense is designed to project the image more perpendiculary to all pixels on the image sensor, less light is probably lost to the inside of the camera body. |
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#14 |
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So with the extension tubes then, is it because you loose light you loose DOF because you have to stop down to compensate for the lose of light?
What are the disadvantage of the close-up lenses (mount on front of a lens). |
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#15 | ||
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fofa wrote:
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With a lens wise open, you will have a shallower depth of field because the focusing distance is less when an extension tube is used. With a lens wide open, you will have to use a longer shutter speed becasue less light is getting to the image sensor when an extension tube is used. fofa wrote: Quote:
Also, close up lenses are additional optical elements, and whenever you add optical elements to an optical system, you decrease sharpness and increase distortion. The effect of a single close up lens won't usually be very significant, but if they aren't good quality and you use them together, it will affect image quality. Extension tubes, on the other hand, don't affect the optics, so if you start with a good lens, you'll get a good image. But close up lenses are cheaper and simpler to use. |
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#16 |
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I'll throw a couple ofcomments into this discussion, only because there's one drawbackto both extension tubes and close-up lenses that hasn't been mentioned. When you use them, you lose the ability to focus to infinity. Now if all you are doing is photographing your tiny subject (I do mostly flowers, to give you a frame of reference) it's not a problem. If you want to take a picture offield of flowersalso, you have to remove the extension tube and remount your lens (or remove the close-up lens). I've taken a number of excellent pictures using a sharp prime lens and a home-made extension tube (which started out in life as a very cheap, poor quality teleconverter that my father had bought 25+years ago), but the fiddling got old after a while, since Itake a lot offlower pictures. Ibought an inexpensive macro lens and have felt much less frustrated (though now a year laterI'm thinking about upgrading the lens). It'spartly a trade-off between cost and convenience.
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#17 | |
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mtngal wrote:
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But I beleive that even a standard lens on anextension tube(s) will get closer than even the 'macro-est' of macro lenses. Close up lenses fall somewhere in between, but if you want to also focus to infinity, close up lenses are easier to remove than extension tubes. |
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#18 | |
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TCav wrote:
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And your point of the close-up lens being easier to remove is really significant! |
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#19 | ||
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mtngal wrote:
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I used to use a bellows on my srT-101 and -202, and I could focus on the specs of dust on the objective lens of my 50mm f1.4. (As I recall, the depth of fieldwas pretty shallow, too; around1/32".)The same effect should be possible when using extension tubes in combination. I haven't looked, but I don't recall seeing the specifications on any macro lens that listed a minimum focusing distance of zero. |
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#20 |
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OK - now I see what you are saying, thanks for explaining what you meant and of course you are right (I tried to say the same thing but not as well as you did).
Originally I thought very little about close-up lenses because of the adding another element aspect. The one I had tried was poor quality and I wasn't impressed at all. However, the macro lens I ended up buying (very inexpensive one) comes with a "matched adaptor" to allow it to go to 1:1 - essentially a close-up filter. It doesn't take away from the sharpness of the lens or cause any flaring or affect the images at all (other than the focus), so I've revised my opinion of them in general. They are much easier to deal with than extension tubeswhen you want to focus to infinity, so I wouldn't necessarily rule them out for macro pictures (though I would buy the best I could find). But it's also one of the reasons why I'm now thinking of upgrading the lens to something else. |
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