Flash or macro?

[HiFiGuy1]

HiFiGuy1-


I think your picture is fine. Many people like the narrow depth of field effect.


However, if you want to get the whole thing in focus, shooting from further away with a longer lens won't help. All that matters is f/ number (and how you frame the picture). So the only thing you can do to get more dof is to stop down. It gets worse as magnification increases. Look how tiny the depth of field is on this grasshopper picture:





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It was also taken at f/5.6, and I used a 100mm macro lens (with extension tubes). If you looked at a 1-1 crop of this picture, you would see that not even the entire *eye* of the grasshopper is in sharp focus.


This is one of the tricky aspects of close-up photography: the more you magnify, the smaller your depth of field. So for closeups you have to stop way down to get your subject in focus (notice the narrow dof in EdN's picture, even though it is at f/14) . When you stop down, though, it is tough to get enough light. And you stop way down, diffraction becomes an issue. Worse, both the light and diffraction issues get worse at a given f/number as magnification increases... TTL metering be blessed!


If it was easy, it wouldn't be so much fun.


I guess

Jon,


Okay. I understand the DOF issue as it relates to f number, I think. I also get the depth compression with longer focal length and closer subject proximity. What I guess I don't understand is, in my flower shot, I have parts of the flower cluster already starting to be out of focus, yet the leaves and mulch, which I'd like to be a featureless blur of background color, are all too distinguishable. With my limited knowledge (I promise I'm trying to learn!), I would have thought that increasing the f number to f/8 or f/11 would have reduced the background bokeh, given the same subject distance and focal length, though it would have fixed the focus on the cluster itself. How do I achieve both goals without a longer focal length? For instance, if I had been using a 200mm, and say f/8 or f/11 to get the whole cluster in focus, with the same composition (and therefore further from the subject), wouldn't I have achieved my goal? Or would the increased distance necessary for the equal composition negate my depth compression and give me anequal bokeh diffusionto the current shot?



Does a macro's 1:1 magnification allow closer shots with a greatly increased distance compression? Is thata different way of saying what you did about the DOF being less with higher magnification? In other words, cana 100mm macro lens, opened up to 11 or 14, give both greater diffusion in the background and allow the subject to be in focus, if that is what I want to achieve? If not, it seems like I might be better off saving up for the 70-200 f/2.8 L IS that I ultimately feel destined to own. [] Then I could use it at or near 200mm, with f/5.6 or 8, and just get as close as possible for the compositions. Then I'd have depth compression with great diffusebackground blur behind the subject, but sharp, crisp images of the subject itself. Or are these just two different ways to achieve the same end result? Is that possible?


Also, am I being hampered by the fact that my camera isAPS-C? Is a FF sensor going to give me better results, or at least what I'm describing here as my desire for this shot?

[Jon Ruyle]

So I totally misunderstood your question.


Sounds like you understand the situation at least as well as I do It is true that most people feel that backgrounds are more blurry if the focal length is longer. In your case, a longer lens might have helped some. However, my guess is that the best solution is to change the angle to get a background you like better. Tiny blades of grass turn into a sea of green more easily than big leaves.


It is also true that the macro will allow more blur at a given f number if you get closer, but of course, this doesn't help you here. On the other hand, if you take true macros (1x magnification and beyond) you'll probably seldom have to worry about blurring the background. You'll have the opposite problem (as I did with the grasshopper).


FF won't help you. You get less more bakground blur with a given framing, true, but only because you have less dof. The only difference with a larger sensor is that the lens will seem shorter (which is the opposite of what you want... if anything, moving away and cropping might have helped).


BTW, I also own the 70-200 IS, and use it for medium close-ups, but I don't think I've ever used it for the reason you're describing. And I use the macro for closeups far more.

[HiFiGuy1]

help you. You get less more bakground blur with a given framing, true, but only because you have less dof. The only difference with a larger sensor is that the lens will seem shorter (which is the opposite of what you want... if anything, moving away and cropping might have helped).
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This is more, correct? I inferred that from the following part about less DOF. That is what I was thinking, too. I agree, I want the lens to seem longer, so I guess I am lucky for now to have the APS-C. I am nowl thinking that, if I had a macro lens, I could compose the shot the same, use a smaller aperture to create just slightly more DOF on the subject itself, but the exaggerateddistance compression of the macro would allow me to get the blurring in the background I want. Does that seem reasonable? The more I think about it, the more I see that I really need the EF 180mm Lmacro[], but that is definitely not happening, at least not today!

[Jon Ruyle]

I meant more, of course. Sorry...


I'm not sure you need the 180mm... the 100mm macro is great. And if you want to do macros beyond 1x, the 100mm might even work better, since extension tubes should have a greater effect on the shorter focal length. And for more moderate closeups (butterflies, flowers, etc) I find that the 70-200 IS with extension tubes works well (I like IS for this). Of course if I could afford the 180mm, I might feel differently about it


I'm not sure what you mean by exaggerated distance compression of the macro. If you compose the shot the same, you don't get any different distance compression than you do with any other 100mm lens.

[HiFiGuy1]

Okay, so the magnification advantage aspect of being a macro doesn't affect the distance compression? I wasn't sure, since the magnification was higher with the macro lens. I didn't know how that affected things other than the ability to get physically closer to a subject. I guess I am more confused than ever now why I even want a macro at all. I thought I got it, but as this unfolds I am understanding that apparently, macro or not, a 100mm lens will pull in the same shot at 1.5 ft (sensor to subject)that a 200mm lens can do from 3 ft. So can anyone help me clearly understand why I want a macro at all? Otherwise, the 70-200 f/2.8 IS is starting to look more attractive, even though that means I'll have to save for a while.

[Jon Ruyle]

The macro lets you focus closer, thus gaining greater magnification. With the 100mm macro at minimum focusing distance (about 200mm), your field is the size of your image sensor. Typical lenses don't allow you to get anywhere near that much magnification. The 70-200 f/2.8 IS can't focus closer than about 1400mm.


If you don't want to focus closer than typical lenses do, there is no reason at all to get the macro. The idea is to get pictures of tiny things, not to get more background blur.


It is true that when you magnify you get very diffuse background blur and narrow dof. But if you take a picture- framed the same- with two different 100mm lenses, one macro and one not, there is no difference.