Tele-extender on macro ? (Page 2): Use an extension tube rather than a TC to double the size of your macro image. There's no loss of light, just a shortening of the working distance.

Bobspez Loc: Southern NJ, USA

Use an extension tube rather than a TC to double the size of your macro image. There's no loss of light, just a shortening of the working distance. At short distances I find it easier to move the camera to focus the lens.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

AK Grandpa wrote:

If I put my 1.4 tele-extender on my Nikon DX 40 mm / 2.8 micro (macro), does that then make it a now a 56 mm macro (effectively 79mm) ?

I understand that I'll loose an f-stop . . .

Are there any advantages to doing this?

Not sure about the 40mm, but I routinely use a 1.4X on my 150 and 180 macros - a slight penalty (amounts to a 5% loss in sharpness), and slower autofocus, in exchange for a larger image - I manually focus when I am really close anyway.

Apaflo Loc: Anchorage, Alaska

Bobspez wrote:

Use an extension tube rather than a TC to double the size of your macro image. There's no loss of light, just a shortening of the working distance. At short distances I find it easier to move the camera to focus the lens.

There is a loss of light with extension tubes. And yes there is a shorter working distance. Also if the lens being used has an Internal Focus design (the front of the lens does not extend when focusing) the image quality will be degraded by the extension due to added aberrations and astigmatism. A TC may have more light loss for a specific magnification, but the focal length is actually increased and the working distance stays the same. TC's used at macro magnifications only use the center, most accurately ground, portion of the glass elements and thus have significantly better results than are typical when using a TC at lower magnifications for general photography.

tsca Loc: USA

AK Grandpa wrote:

If I put my 1.4 tele-extender on my Nikon DX 40 mm / 2.8 micro (macro), does that then make it a now a 56 mm macro (effectively 79mm) ?

I understand that I'll loose an f-stop . . .

Are there any advantages to doing this?

The Nikon 1.4 TC isn't compatible with the Nikon DX 40 mm per Nikon's chart:

http://www.nikonusa.com/en_INC/IMG/Assets/Common-Assets/Images/Teleconverter-Compatibility/EN_Comp_chart.html

Welcome to UHH!

Bobspez Loc: Southern NJ, USA

I use the Nikkor M2 extension tube on my Nikkor-P 55mm macro lens. It doubles the magnification to a 1:1 macro lens of 110mm. Since the extension tube has no lens, why would there be a loss of light? The macro extension tube also has a mask and only uses the center of the lens as well. See attached pic of the M2.

Apaflo wrote:

There is a loss of light with extension tubes. An... (show quote)

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blackest Loc: Ireland

Bobspez wrote:

I use the Nikkor M2 extension tube on my Nikkor-P 55mm macro lens. It doubles the magnification to a 1:1 macro lens of 110mm. Since the extension tube has no lens, why would there be a loss of light? The macro extension tube also has a mask and only uses the center of the lens as well. See attached pic of the M2.

Straight forward enough if you think about it, when you use the extender you move the lens further away from the sensor just like a projector really. This makes the picture bigger but only part of it is being captured by the sensor since the light is spread over a larger area less photons reach the sensor. Even with the mask it just means the spillage of light isn't reflected off the mirror box. The mask is probably a good idea since it may reduce the chances of an internal reflection reaching the sensor and degrading your image.

Bobspez Loc: Southern NJ, USA

Thanks blackest. Maybe tomorrow I will take a couple of pix, one with and one without the extender, using the same iso, aperture and exposure. Just the focal length will be different. I'll crop the subject the same size in both pics and compare. Should tell me if the one with the extender loses light and/or pixels. Even if it does, I'm thinking it will gain detail. I'll post the results here. At least it will document what an extender will do. I'll use a readily available subject. Others can run their own tests with the TC. On the plus side a used Nikon M2 2x extender costs less than 20 bucks on ebay.

blackest wrote:

Straight forward enough if you think about it, whe... (show quote)

Pablo8 Loc: Nottingham UK.

Bobspez wrote:

I use the Nikkor M2 extension tube on my Nikkor-P 55mm macro lens. It doubles the magnification to a 1:1 macro lens of 110mm. Since the extension tube has no lens, why would there be a loss of light? The macro extension tube also has a mask and only uses the center of the lens as well. See attached pic of the M2.

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If one uses an extension tube, the lens is moved further away from the sensor than would be the norm without the tube. As in the inverse square rule regarding moving lights further away from the subject, there is 'Light-Loss.' In the case of cameras with TTL light readings, this is accounted for / adjusted automatically.
Regarding the original posters point...I have the Sigma 150mm Macro lens and the 'Dedicated' 1.4 extender. They work well together, otherwise Sigma would not describe the extender as 'Dedicated'.

Bobspez Loc: Southern NJ, USA

You are correct, there is light loss with an extender. I took a few test pics with the same light source, and settings, with the macro lens at minimal focusing distance, and the extension tube does lose some light. At minimal focusing distance you actually get more pixels on the subject with the extender because what fills the frame with the extender must be cropped on the pic without the extender to match the area taken. Regarding detail, I forgot how difficult macro shooting was, lining up the plane of the subject with the plane of the lens to maximize the in-focus area. That difficulty is magnified with the extender (and probably with the TC as well).

Pablo8 wrote:

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Bobspez Loc: Southern NJ, USA

Hi blackest,
Attached are two test pics taken with the Nikkor-P manual focus macro lens, 55mm, f3.5, illuminated by a desk lamp. One was taken with the extender, one without. The lens was set to the minimal focus distance and I focused by moving the camera. The shot with the extender was taken at f5.6. I had to raise the aperture to f8 for the shot without the extender to keep the coin from being blown out. So you are right about the extender losing light. I cropped both photos to just show George Washington's face on a quarter. The crop with the extender wound up at 1.27MB, the crop without the extender just 344K. It seems to me the shot with the extender captured more detail, maybe because it contains more pixels.

blackest wrote:

Straight forward enough if you think about it, whe... (show quote)

GW-f5.6.M2-2x-extension tube-crop 1.27MB crop

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GW-f8-344K crop
GW-f8-344K crop...

(Download)

blackest Loc: Ireland

Bobspez wrote:

Hi blackest, br Attached are two test pics taken w... (show quote)

It's nice when the practice meets with the theory. So many times there is a whole load of technical talk spouted out that you would need a specialised degree in to be able to follow let alone prove or disprove and in the end its the photographs which matter. Not how many big words and technical theories that can be used.

So glad i had the theory right, feel so ... when I get it wrong, at least I admit it. :)

ballsafire Loc: Lafayette, Louisiana

Congratulations! Your experiment turned out well-- BUT when you use the term "extender" you should use the term "tele-extender sometimes referred to as the initials "TC" which stands for tele-converter" that's where confusion can set in when distinguishing from a hollow extension TUBE. It is shameful that the two terms -- tele-extender and tele-converter means the same thing--(if I have it right).

Bobspez wrote:

Hi blackest, br Attached are two test pics taken w... (show quote)

blackest Loc: Ireland

ballsafire wrote:

Congratulations! Your experiment turned out well-- BUT when you use the term "extender" you should use the term "tele-extender sometimes referred to as the initials "TC" which stands for tele-converter" that's where confusion can set in when distinguishing from a hollow extension TUBE. It is shameful that the two terms -- tele-extender and tele-converter means the same thing--(if I have it right).

yes if he used a teleconverter of some kind but his extender was a tube so no. :)

I think you confused yourself. :)

Apaflo Loc: Anchorage, Alaska

blackest wrote:

yes if he used a teleconverter of some kind but his extender was a tube so no. :)

I think you confused yourself. :)

The your unusual use of the term "extender" in this thread has made it somewhat difficult to follow.

The term "extender" does not normally mean an extension tube. In fact Canon uses the term "extender" for most of their teleconverters. This confusion has been exacerbated by more than one comment saying the "extender" increased the focal length, which extension tubes do not do but a tele-extender does. A reader has to re-verify, by comparing context, that the comments are actually talking about extension tubes rather than extenders.

Bobspez Loc: Southern NJ, USA

The correct Nikon terms are Nikon M2 Extension Tube, and Nikon Teleconverter. In my posts I used the terms extension tube and extender interchangeably. I didn't realize Canon used the term extender for what Nikon calls a teleconverter. I guess I know now. Thanks Apaflo.

Apaflo wrote:

The your unusual use of the term "extender&q... (show quote)