50mm with tubes vs Macro lens

[zedbra]

I have the Nikon 50mm f1.8 prime lens (the nifty 50) and since seeing the clarity of shots with that, I am very disappointed with my other lenses (Sigma 70-300mm APO and Nikon 18-70mm kit lens). I find that the difference in quality is huge and the clarity of the 50mm can make even a dull shot look great.

I've managed to take some fairly good macro shots with my Sigma but the quality is very poor so it ruins some otherwise great shots. I have bought a lens to put on the front of my 50mm to turn it into macro, but the extra optics lower the clarity considerably. Also, I then have to get extremely close to the subject before it will focus and the depth of field is tiny.

Sorry to waffle, I'm getting to my question in a sec. I've read mention of Kenko tubes and I'm wondering if they will solve all my problems, including the main problem which is my current lack of money to buy a decent macro lens! I'll list my questions if that's ok...

* Will using the tubes mean I have to get very close to the subject (a few centimeters) to focus, and what sort of depth of field can I expect compared to using my macro lens mounted in front of the 50mm?

* Do tubes actually cause the image to be magnified more as well as decreasing focusing distance?

* As I understand it there are no optics, so will the results be just as crisp and sharp as using the 50mm on it's own?

* I imagine I'll lose some light through a tube? What exactly are the disadvantages of tubes compared to spending several hundreds of pounds on a dedicated macro lens?

Many thanks for reading this and for any help you can give me.

Geoff.

 

[BRASH]

I have the Nikon 50mm f1.8 prime lens (the nifty 50) and since seeing the clarity of shots with that, I am very disappointed with my other lenses (Sigma 70-300mm APO and Nikon 18-70mm kit lens). I find that the difference in quality is huge and the clarity of the 50mm can make even a dull shot look great.

I've managed to take some fairly good macro shots with my Sigma but the quality is very poor so it ruins some otherwise great shots. I have bought a lens to put on the front of my 50mm to turn it into macro, but the extra optics lower the clarity considerably. Also, I then have to get extremely close to the subject before it will focus and the depth of field is tiny.

Sorry to waffle, I'm getting to my question in a sec. I've read mention of Kenko tubes and I'm wondering if they will solve all my problems, including the main problem which is my current lack of money to buy a decent macro lens! I'll list my questions if that's ok...

* Will using the tubes mean I have to get very close to the subject (a few centimeters) to focus, and what sort of depth of field can I expect compared to using my macro lens mounted in front of the 50mm?

* Do tubes actually cause the image to be magnified more as well as decreasing focusing distance?

* As I understand it there are no optics, so will the results be just as crisp and sharp as using the 50mm on it's own?

* I imagine I'll lose some light through a tube? What exactly are the disadvantages of tubes compared to spending several hundreds of pounds on a dedicated macro lens?

Many thanks for reading this and for any help you can give me.

Geoff.

The tubes will take you closer than the 50mm lens on its own which ain't great if you are shooting insects. The cheeper ones don't have contacts so no AF. Thing is with macro AF is not needed.

You wont lose a lot of light in the tubes and as you say no glass so no real IQ issues.

Hope this helps.

 

[tdodd]

What exactly are the disadvantages of tubes compared to spending several hundreds of pounds on a dedicated macro lens?

Working distance and DOF. A proper macro lens will give you 1:1 reproduction at a greater working distance (distance from front element or filter thread to the subject) than a bog standard 50mm lens and tubes. Roughly speaking, if you want 1:1 reproduction from a 50mm lens you need 50mm of tubes.

I shoot with a Canon 40D and with my 50mm f/1.8 and 48mm of tubes (12+36) the maximum working distance I can get from the front of the filter thread is 6cm and the minimum is about 5cm. That's not much space to give a nervous insect and the DOF at that distance is wafer thin.

If you look at the table down the page here - http://www.the-digital-picture.com/Reviews/Canon-EF-180mm-f-3.5-L-USM-Macro-Lens-Review.aspx - you will see that a proper macro lens will give you a MWD of between 9cm and 24cm depending on the lens.

The problem with minimal DOF is that you have to stop down a lot, perhaps so much that you start to see diffraction softening. Then there is the issue of light. If you crowd your subject and stop down to, say, f/16 then you're going to struggle to light your subject well and will have very long exposure times or horrendously high ISOs. You may well need flash and a specialised flash diffuser in order to send the light where you need it and with the right quality/quantity. If your subject is static and you have a tripod then there is no problem, but otherwise.....

Have a look at posts 2229 and 2234 in this thread for examples of what the Canon nifty and some tubes can do....

http://photography-on-the.net/forum/showthread.php?p=5061627#post5061627

Here's another thread, showing tubes in use on a 70-200 lens....

http://photography-on-the.net/forum/showthread.php?t=537294

 

[zedbra]

Thank you both for all that very useful information. I can't look at the photos you linked to at the moment because I'm writing from my phone, but I'll definitely look later. However, some of what you've said is already convincing me that tubes aren't the way to go for me. It sounds like the distance between the subject and lens, and also DoF, is as bad with tubes as it is with the macro attachment lens I currently have for my 50mm prime.

I've been doing some more reading on this and many people are recommending the Vivitar 100mm Macro lens, as it's very sharp and also very cheap. So maybe that's a better option. I'm just so anxious that the results be a lot sharper than I'm currently achieving.

When I get to my computer I'll look at those images and will also try to find some examples taken with the Vivitar. I'll also have a look at that chart you linked to after sending this as that may answer some more questions hovering in my mind.

Thanks again,
Geoff.