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Old Feb 17, 2008, 11:21 PM   #1
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On the Canon site it shows that with the 100mm f2.8, the closest focusing distance is about 1 foot. It also says it affords a "long working distance of 5.9". I understand the first spec but not the second. Also, what makes a macro a macro anyway? Is it that the lens is specialized to work only in close proximity to magnify the subject? Telephoto lenses seem to all have a "macro" designation at the far end. But you are telescoping to that point so you don't have to stand close. I would assume that those don't match the quality of a dedicated (good) macro and also that the magnification can't be as powerful. Thanks in advance, Janet
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Old Feb 18, 2008, 4:50 AM   #2
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Hello Janet,

I'll try to answer quick. I spent the best part of an hour writing my last reply to you, as clearly as I could!

Basically the "closest focussing distance" standard is written from the BACK of the lens (that is, where the lens meets the camera). So if you have a closest focussing distance of 50cm but your lens is 15cm long, then in theory you should be able to focus on something at 35cm away from the FRONT of your lens. I'm 90% sure this 35cm is referred to as the "working distance". (sorry I work in cm, not imperial - though I know 12 inches = 1 foot). and 1 inch is 2.54 cm. anyway... besides the point!)

A macro lens is specially designed to be able to focus CLOSE - which will allow you to get LARGER images of (usually) small things like insects, flowers, coins, blades of grace, your finger, etc. Because you know from life, that the closer your finger is to your eye the bigger it "appears". However unless you know how to use the camera (e.g. it needs to be REALLY steady with macro photography) and lighting can be tricky at close working distances, you might not often need to be "as close as your lens can get you" - e.g. with your 100mm f2.8 lens. Furthermore if you use f2.8 at the closest focussing distance on your 100mm macro lens you will have a VERY think depth of field "dof". That means only a millimetre or two will be in focus, everything else will be out of focus (oof!)

You are right that a dedicated macro lens will generally be able to capture superior quality images than a "zoom lens" which also has "macro capabilities". Maybe the most significant aspect is, as you mention the "magnification ratio". That is, the dedicated macro lens should be able to get you about 1:1 (life size on the SENSOR) magnification, which means you can display on your screen or print out an insect at a LARGE size. A zoom which can do "macro" might only have a 1:2 or 1:3 macro capability, which is still probably fine for 90% of average DSLR users.

I don't have a "dedicated macro lens".... actually I am almost envious of your 100mm f2.8 lens, that is a great macro lens. However I have got many flower shots and even some insects with my 28-135mm lens and my 18-55mm ("kit" lens), which I'm very happy with. For one example, taken with my 28-135mm zoom lens is posted below.

Please let me say (and no reflection on you, neither is this any praise for myself, I consider myself a "modest amateur")... but there are many people with simple cameras or the "basic lenses" who take much superior photos to other people who have bought the best and most expensive and most "capable lenses". 90% of the success of "amazing" photography is to do with the photographer, rather than his or her tools! I'm learning something every month about how to improve my photography techniques.. I'm glad you seem to be keen to learn lots too. Enjoy the learning. Treat it as a valuable and beautiful part (or "art") of life!


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Old Feb 18, 2008, 3:53 PM   #3
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Hi Paul, thank you for responding. Your explanation is very clear. Although it probably doesn't appear to be the case (given what I've invested in at such an early stage) I absolutely know the truth of your last paragraph. Good equipment doesn't makea goodphotographer any more than a Ferrari makesa good driver. However, the Ferrari will makeMs. Joe Coollook pretty lame during a run whenshe's slowing everyone down and it's obviousshe bought more car than she can handle...not that I own a Ferrari

Thanks again for your time. As well as being skilled, you are a very kind person. That's a rarity these days.

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Old Feb 19, 2008, 12:58 PM   #4
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Canon literature refers to the distance from the lens to create a 1X or life size image. Your lens is a very capable tool ,have fun with it. I have enjoyed floral macros for years. It has become such a passion that I now garden with photography in mind.


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