Whats the difference between....

[DigiDiva]

A step down filter and an extension tube when it comes to macro photography? You might think that its a silly question, as one steps down your lens and the other 'steps it up' but I'm confused.

I have a Canon 100MM macro lens and want to get a little bit closer. When I google this, I get conflicting advice. Some suggest a step down filter and some say buy extension tubes.

Can anyone explain what they do and which I need? I'm looking at exploring macro photography more closely.

Thanks.

[wavemachine]

Not sure what you mean by a step down filter, you can get step down rings which will allow a bigger filter to be attached to a lens smaller than it was designed for.

You can get macro magnification filters which will screw onto your lens essentialy they act like a magnifying glass or as you have correctly identified you can get extension tubes which fit between the lens and the camera.

The main disadvantage with extension tubes is with cheaper models you can loose autofocus, you will get less light hitting the sensor so this needs to be considered also a slight loss of DOF.

Filters can be a bit tricky to use and also you can get distortion having said that you can still get good results.

Given that you have an 18MP sensor you do have a lot of room for manouvre with cropping in PP to enlarge your subject of course.

I have the 100mm EF Macro and know what you mean sometimes I want to get closer and would love one of these but really cannot justify the cost plus they are a pig to use.

[DigiDiva]

Sorry I did mean a step down ring....was writing a quick email in my lunchtime. Love the link you sent and I shouted 'How Much' when I saw the price!!!!

Are you saying that my camera is good enough to pick out very minute detail and can handle a crop to show off this details? If so, then maybe I don't need either!

Thanks Dave. Still not sure I understand the difference though lol

[donoreo]

I have these: http://www.bhphotovideo.com/c/produc..._Tube_Set.html They are cheaper than Canon or Kenko, but are well made. All metal fittings. Using them with my 50MM f/1.8 they work really well.

You can go with cheap metal tubes, but as mentioned you will lose aperture control and autofocus (I always manually focus when doing macro). I have a set of these too since they were $8 and I got them first.

[wavemachine]

Originally Posted by DigiDiva

Are you saying that my camera is good enough to pick out very minute detail and can handle a crop to show off this details? If so, then maybe I don't need either!

Thanks Dave. Still not sure I understand the difference though lol

Yep you have 18MP (IRQ you have a 60D) so get as close as you can and you will be surprised at how much detail is captured but the closer you can get the better I would have a play if you are not happy then have a look at the alternatives.

As donereo mentioned for macro work it is best to manually focus, use a tripod if possible and live view is a godsend for accurate focus as you can focus and use the zoom button to see how sharp it is.

[jet_kit]

[QUOTE=donoreo;81536]I have these: http://www.bhphotovideo.com/c/produc..._Tube_Set.html They are cheaper than Canon or Kenko, but are well made. All metal fittings. Using them with my 50MM f/1.8 they work really well.

Hi Don,

These are pretty cheap and since extension tubes have no optics, as long as they don't let any light in and your lens doesn't fall off in use, it's hard to justify a more expensive set.
I just need to check out whether they make them to fit proper cameras. LOL.

[DigiDiva]

Originally Posted by donoreo

I have these: http://www.bhphotovideo.com/c/produc..._Tube_Set.html They are cheaper than Canon or Kenko, but are well made. All metal fittings. Using them with my 50MM f/1.8 they work really well.

You can go with cheap metal tubes, but as mentioned you will lose aperture control and autofocus (I always manually focus when doing macro). I have a set of these too since they were $8 and I got them first.

To help me try to understand what they do......You say use them wit your 50MM prime lens so can yu explain what they do to your lens that it can't do as a 50 mm lens?

[DigiDiva]

I have 'mastered' normal macro potography with my 100 mm macro lens. I use manual focus (on live view), I use manual settings for aperture and shutter speed, use a tripod and a remote shutter release, so Im happy ih ave the skills and equipment for that. What Im lacking is the understanding of what equipment I need so my lens gets even closer. I hope im not being an idiot here, but Im just not understanding what the different bits of equipment to do my lens to change it.

[StephenBatey]

I won't frighten by using an equation, but there is a link fixed by the laws of optics that relates the focal length of a lens, the distance of the subject and the distance behind the lens that a sharp image of said subject will be focused. As the subject gets closer, the sharp image gets further away, assuming that the focal length doesn't change..

Before autofocus, the best lenses focused by moving them away from the camera body in a focusing mount or by using bellows. As the subject got closer, you needed more distance, and eventually the focusing mount built in to the lens was insufficient. You then used tubes or bellows to increase the separation. Hence what they do is let you focus closer.

After autofocus, lens designers began to cheat a little to make the autofocus faster and less energy expensive by focusing by altering the focal length of the lens so that the lens/image distance didn't have to change much and therefore the lens didn't have to be physically racked out.. But there is still a limit as to how much you can change this.

Close up lenses work differently. When the subject is one focal length in front of a lens, the in focus image is located at infinity. Hence, put on a close up lens, and the camera lens can be set at infinity and a subject one focal length (of the close up lens) will be in focus.

Close up lenses are usually marked with their focal length expressed in diopters, 1 diopter being the reciprocal of the focal length in meters. The reason for this odd convention is that when you stack them, the diopters are additive - a 1 diopter lens lets you focus on a subject 1 meter away; add another and as 1 + 1 = 2, the subject can now be 1/2 meter away and be sharp.

[donoreo]

Originally Posted by DigiDiva

To help me try to understand what they do......You say use them wit your 50MM prime lens so can yu explain what they do to your lens that it can't do as a 50 mm lens?

I can focus closer. If my normal focusing distance is 24 inches, the tubes can make it less than an inch (all hypothetical numbers, too lazy to look it up).