Whether it's good or not, to use a macro extension tube.

There are sure a lot of you had or having the question.
Well, whether it's good? Let's find out!
Today, I'll just upload two picture to show the difference between using and not using.

Macro extension tube lenses are accessaries for us to be able to take close-up pictures, especially really small ones. At this time, macro expert may take out their macro lens and take the photo. That is a way to do this, but it will provide us a better effect to use.

Here are two pictures that taken without and with the macro extension tube on. I think you could tell the difference all by yourself.

Extension tubes can be a great way to introduce yourself to macro photography without going to the expense of a macro lens, and depending on the lens you use them with, can get you even more magnification than the 1:1 of most macro lenses.

Forget where I read, for the IQ: Macro lens > Macro filter > Macro extension tube.

Extension tubes should not simply be thought of as a way to achieve 'macro'...it can be used as a way to simply focus closer than the focus mechanism of a lens will normally allow. For example, focusing a 300mm f/4 lens closer than 1.5m, to capture a 2" x 3" area within the frame.

x_tan wrote in post #14136024
Forget where I read, for the IQ: Macro lens > Macro filter > Macro extension tube.

I thought the tubes were generally considered to be better than filters when used properly? There's no glass element in them so nothing to degrade the image, it's just a trick to focus a little closer and would be as good or as bad as your lens allows.

elogical wrote in post #14136891
I thought the tubes were generally considered to be better than filters when used properly? There's no glass element in them so nothing to degrade the image, it's just a trick to focus a little closer and would be as good or as bad as your lens allows.

Ok, found some of the web pages:

Can't find Filter better than the tube yet,

MACRO EXTENSION TUBES & CLOSE-UP LENSES

And:

Close Up Filter, Extension Tubes or Macro Lens?

Nikon 50 f/1.4 with 13+21+31mm extension tubes

Wilt wrote in post #14136028
Extension tubes should not simply be thought of as a way to achieve 'macro'...it can be used as a way to simply focus closer than the focus mechanism of a lens will normally allow. For example, focusing a 300mm f/4 lens closer than 1.5m, to capture a 2" x 3" area within the frame.

You let me know the extension tubes better, thank you.

x_tan wrote in post #14137026
Ok, found some of the web pages:

Can't find Filter better than the tube yet,

MACRO EXTENSION TUBES & CLOSE-UP LENSES

And:

Close Up Filter, Extension Tubes or Macro Lens?

Nikon 50 f/1.4 with 13+21+31mm extension tubes

Compare to 1:1 macro using a Nikon 105mm f/2.8 VR. Image quality wise, it is better than using extension tubes.

Having seen your explanation and your pictures, I think extension tubes give us more magnification, that's the reason why, in the same condition, it can only provide us with darker pictures or maybe a little bit fuzzy on the edge of the photo

burtsun wrote in post #14137133
Having seen your explanation and your pictures, I think extension tubes give us more magnification, that's the reason why, in the same condition, it can only provide us with darker pictures or maybe a little bit fuzzy on the edge of the photo

I read the original web page again, I'm not sure now: as they might be just DOF different between the tube and the Micro lens.

Anyway I use 100mm Macro and adding up to 20cm tubes, which can give me ~ 3x magnification.

IMO extension tubes don't degrade images due to added glass elements like close up filters do. I have never considered trying close up filters to achieve close up/macro images. To me they are like going to Big Lots to get a pair of reading glasses off the rack, they work but at what expense?

burtsun wrote in post #14137133
Having seen your explanation and your pictures, I think extension tubes give us more magnification, that's the reason why, in the same condition, it can only provide us with darker pictures or maybe a little bit fuzzy on the edge of the photo

Yes. One thing to understand is that the aperture setting of any lens is only accurate when it's focused to infinity. The moment you extend the lens to focus closer than infinity, you run into the inverse square law that means you're diminishing the amount of light reaching the sensor.

In most lenses, the difference is small and negligible (although people who owned the bellows-focusing Mamiya TLRs and SLRs are well-acquainted with it and macro lenses are designed to compensate for it). When you use extension tubes, however, you're moving the lens out much farther than the designer intended...so you have to compensate manually or suffer underexposure.

In addition, the lens is designed for maximum sharpness within a given focus range (actually, at a given focus point); again, extension tubes move the lens beyond the range it was designed.

But TANSTAAFL rules, and you have to weigh the compromises for yourself.

The internal focus mechanism of even macro lenses is limited in its range of motion. A typical macro lens might be able to give 1:2 or 1:1 magnification within its zoom range. But some very specialized macro lenses might be able to achieve 5:1.

In general, extension tubes simply 'move the optics further away from the focal plane than its internal focus mechanism allows', so that it focuses closer. Done in moderation, it permits the 300mm f/4 lens to focus closer than its usual 1.5m close focus limit. Done in greater amounts, it permits macro shots where the subject is 1:2 or 1:1 (or more) on the sensor.

Extension tubes are limited by the quality (or lack of quality) of the lens it is attached to. A 400mm lens really is designed for long distances, and using it to shoot at something 0.5m at macro scale assumes that its optics perform well at very short distances -- likely a bad assumption. For example, it might suffer from curvature of field, where a flat plane (e.g. paper currency) is NOT captured in focus across the entire frame. So in that sense, extension tubes 'magnify' or exaggerate inherent weaknesses in the optical design of the lens, whereas a true macro lens was designed for very close distances and to preserve flat plane focus.

Zero difference in DOF, whether you use true macro lens or extension tube.

But even macro lenses have to have their aperture compensated, because the 'magnification' is caused by spreading the available photons over a larger area of the sensor. Usually now we simply fail to notice because of TTL metering. Regardless of the technique used to achieve close focus -- internal focus threads or extension tubes -- the effect on exposure is totally related to the final magnification of the subject on sensor.

Macro lens > extension tube > macro close up lens
...because the macro lens works close much better than a lens designed for longer distances

Slight clarification, Wilt. If the macro is (as more and more are) internal-focusing, the effective aperture won't necessarily be the same as that you'll get by simply putting an extension tube on the lens, with the lens set at infinity.

For instance, the Canon 100 macro (non-L) is, IIRC, around a 72 mm f.l. when at 1:1. Putting 100 mm of tubes behind the lens, focused at infinity, would give you about an f/5.6 effective aperture at f/2.8 indicated; if the aperture maintains a constant diameter (opening), focusing to 1:1 using the helical and internal focussing would give it an aperture of closer to f/5.1 (about 1/3 stop faster), and a consequent slightly shallower DoF.

Since close-up lenses work by altering the effective focal length of the lens they're used with, they have less effect on the real aperture of the lens combo at closer focus, and you'll see a more pronounced difference in DoF between a lens used with close-up lenses and the same lens used with extension tubes at any given magnification.

Jon wrote in post #14138689
Slight clarification, Wilt. If the macro is (as more and more are) internal-focusing, the effective aperture won't necessarily be the same as that you'll get by simply putting an extension tube on the lens, with the lens set at infinity.

Yes, thanks for mentioning that. I knew it, but did not want to mention all of the "'I' before 'E'" exceptions, so as to not turn the post into a doctoral candidate thesis Don't forget about the issue of changing effective focal length in some AF macro lenses, too! Macro discussions were simpler in the days of film cameras and manual focus.