Macro Lenses Vs. Prime Lenses

porkphoto · Oct 22, 2009

decado, one option is to get a 50mm prime of your choice and if you want to shoot macro you just reverse the lens.

decado · Oct 22, 2009

porkphoto said:
decado, one option is to get a 50mm prime of your choice and if you want to shoot macro you just reverse the lens.

What? How would that even be possible?

DennyCrane · Oct 22, 2009

It's not.

Dao · Oct 22, 2009

decado said:
porkphoto said:

decado, one option is to get a 50mm prime of your choice and if you want to shoot macro you just reverse the lens.

Click to expand...

What? How would that even be possible?

Reverse the lens and pair it with another lens.

Kind of like join the 2 lenses together with the front lens elements facing each other.

Overread · Oct 22, 2009

I can't give much detailed info on reverse lens macro (which is what is being described above) since its something that I have yet to try out. However I can give you the basic working idea;

It works by taking two lenses and connecting them together using a reversing ring which scews into both lenses filter threads on the front. So lets say you have two lenses, one with a filter thread size of 48mm and another with 58mm - you would need a 48mm to 58mm reversing ring (ebay is a good place).
With both of the lenses mounted this way you control the aperture with the lens mounted on the camera (typically this is the heavier and longer focal length lens, with the lighter shorter one being mounted on the thread) as normal and shoot through the other lens. The effect you get is a magnified image.
However this method works similar to that of extension rings (mentioned in my previous post) so again you lose infinity focus and have avery small working distance to work with. It can also place more strain on your filter threads as well - provided your not using a massivly heavy lens it should be ok, but do keep an eye on it and don't strain the connection. Further this setup is typically used to get beyond 1:1 magnifcation and into the far greater and far harder magnifications - so for starting out it might seem a little much depending on what lenses you use (since differing lenses will give you differing amounts of magnification - there is a formula for this but I don't know it.

decado · Oct 22, 2009

So reversing my 18-55 and putting it on my 70-300 should theoretically give the 70-300mm a very close focus range? Possibly closer than with an extension tube?

Overread · Oct 22, 2009

Yes but there is a reason that lenses like the 50mm f1.8 prime are popular - good quality optics and a wide max aperture (f1.8). That means not only do you get a good image at the end, but also it makes focusing a lot easier since there is more light getting into the camera to view through the viewfinder. The two zooms you have are smaller in their max apertures, so that means less light and their image quality is lower.
By all means you can try it, but chances are your results will be lacking.

decado · Oct 22, 2009

Overread said:
Yes but there is a reason that lenses like the 50mm f1.8 prime are popular - good quality optics and a wide max aperture (f1.8). That means not only do you get a good image at the end, but also it makes focusing a lot easier since there is more light getting into the camera to view through the viewfinder. The two zooms you have are smaller in their max apertures, so that means less light and their image quality is lower.
By all means you can try it, but chances are your results will be lacking.

I probably won't try it, I was just curious.

porkphoto · Oct 22, 2009

decado, I was amazed myself when I first read about this. I took the lens off my 5D reversed it , not even attached, I just held it against the body and snapped a picture. It worked! BTW the camera must be set to AV mode. You focus by moving in or out, towards or away from the subject. Try it, its amazing.

Overread · Oct 22, 2009

that works too - but I don't like it - mostly as it means that DUST! can easily get into the camera. And as you work with macro you will soon come to hate little dustspots on teh sensor (and love the heal tool in photoshop/elements)

Dao · Oct 22, 2009

Normally, the lens, such as the 50mm lens bring the lights from infinity to it's focus. Or, you can say the lens bring the lights from the focus to infinity. (Just a reverse)

So, if the object is at the focus point of the 50mm lens, it will bring the reflected light from the object to the infinity. And the other lens that attached to the 50mm lens will bring those light from infinity and focus it on the sensor/film.

I believe it is how this work. please correct me if I am wrong.