Extension tubes for nikkor 200 mf

[jimcritchley]

I have a Nikkor 200mm macro and i have an option to buy some extension tubes for what i think is a good price. They are Macro Extension Tube 3 extension tubes - 7mm, 13mm, 36mm and male and female adapters, Jin Quan brand and I will be able to get them for around $50 NZD. However, I am unsure on their full role and whether the lens would benefit? Any help please.

[prinothcat]

I will toss this out, and someone will correct or refine it... Extension tubes will increase the magnification, shorten the depth of field, narrow the field of vision. This should allow one to work smaller objects, and better highlight the subject. Be aware that they will also drop the aperture rating slowing the exposure. They will probably require the use of off camera lighting or a ring light, because they will move the subject closer to the lens potentially casting unwanted shadows and blocking light from a shoe flash..... They are generally just hollow tubes, with no glass elements or controls. If your lens was AF instead of MF they would need AF couplings and would cost more. On that note make sure they have aperture control linkages... They may be intended for a completely manual lens set up.

I have no frame of reference as to the price, but seems to me if they are affordable, why not pick em up and play around with them?

[dang]

I will toss this out, and someone will correct or refine it... Extension tubes will increase the magnification, shorten the depth of field, narrow the field of vision. This should allow one to work smaller objects, and better highlight the subject. Be aware that they will also drop the aperture rating slowing the exposure. They will probably require the use of off camera lighting or a ring light, because they will move the subject closer to the lens potentially casting unwanted shadows and blocking light from a shoe flash..... They are generally just hollow tubes, with no glass elements or controls. If your lens was AF instead of MF they would need AF couplings and would cost more. On that note make sure they have aperture control linkages... They may be intended for a completely manual lens set up.

I have no frame of reference as to the price, but seems to me if they are affordable, why not pick em up and play around with them?

Tubes are generally used with shorter lenses to gain the most from them. To achieve life size magnification (1:1) with standard lenses requires using the same amount of extension, as the length of lens used. Therefore, a 50mm is most commonly used. They do cut down on light (as noted), so if shooting manually you'll need to compensate for proper exposure. If you need more information, I have a lot of it available in various galleries here: http://www.dangphoto.net
There's an included chart showing exposure calculations/magnifications for manual tubes.
If you have any other questions, feel free to Pmail me.

[art_spearing_photo]

I have a set of extension tubes that I use occassionally with my 300mm lens. However, this lens is not a macro, and I sometimes need an extension tube to get in closer to a smaller subject. Is your 200mm lens a true macro lens? If so, it should give you the ability to "get closer" to just about any subject except for the extremely small ones. If your lens is a true macro, I would recommend testing it with a variety of smaller subjects, so you can get a good idea how well it does on it's own. You might find that it will focus on the kinds of smaller subjects you are interested in without an additional tube.

[jimcritchley]

Cheers for the info. With regards to art, the lens is a true macro which focuses down to 70cms. Would you guys buy one yourself or just stick using the 200mm on its own?

[dang]

Cheers for the info. With regards to art, the lens is a true macro which focuses down to 70cms. Would you guys buy one yourself or just stick using the 200mm on its own?

I'm assuming this is with a 1:1 reproduction? If not, it's not what would be considered a true macro lens which makes a big difference on outcome.

Manufacturers are a bit tricky in stating some lenses as having macro. They can do this by saying when printed as a 4X5, it's life size. But actual macro lenses yield 1:1 reproduction on a standard 35mm film/sensor frame of 24X36mm. Many longer lenses advertised as having macro ability are actually only one quarter to one sixth this amount.

Another mis-conception is focusing distances can be advertised differently. Be sure when purchasing, you know if actual minimum focus distance advertised is from film/sensor plane, or front of lens. It's to the manufacturers advantage to quote distance from film/sensor, since the length of the lens cuts into the distance dramatically.

As prinothcat stated earlier, be sure they have coupling ability to automatically stop down the diaphragm. Otherwise, you'll need to manually before exposure, and focusing is extremely difficult due to the darkened viewfinder. While this isn't a problem shooting stationary subjects, with live insects it's extremely difficult. Of course, there's always people who wouldn't mind photography dead subjects, though it's not my cup of tea.

One alleberation on prinothcat, adding tubes doesn't cut the field of view. Even though you'll get closer, the background area is unaffected. If for example, the lens has a field of view of 24 degrees, it remains 24 degrees with extension (unless I've forgotten something).

Hope this helps a bit.

[prinothcat]

One alleberation on prinothcat, adding tubes doesn't cut the field of view. Even though you'll get closer, the background area is unaffected. If for example, the lens has a field of view of 24 degrees, it remains 24 degrees with extension (unless I've forgotten something).

I wasn't 100% on that point, I only vaguely remember using E-tubes on a very old Exacta way back in teh day... and I thought it may have reduced the field of view.

[dang]

Chris, it's an easy thing to assume, because focus distance is less and you're closer to background objects too. What actually happens, is a slight change in perspective, which tricks the eye. Since they're (tubes) added to the rear of the lens, angle of view is preset. And you're correct that it has an effect on dof. The higher your magnification, the lesser your dof. A simple rule anyone shooting macro learns quickly, if they weren't aware. It's also good to note that lenses f/stops are rated at infinity, but the "effective f/stop" can be several stops slower when focused for macro, even without tubes. It's not a big deal when metering through the lens, but if using a hand held meter, correction for exposure must be added in.
Here's a rough illustration, which might help explain "angle of view" for anyone less familiar.


Thanks, enjoyable discussion.

[prinothcat]

..you're correct that it has an effect on dof. The higher your magnification, the lesser your dof. A simple rule anyone shooting macro learns quickly, if they weren't aware. It's also good to note that lenses f/stops are rated at infinity, but the "effective f/stop" can be several stops slower when focused for macro, even without tubes. It's not a big deal when metering through the lens, but if using a hand held meter, correction for exposure must be added in.
Thanks, enjoyable discussion.

Cool.. The DOF effects I was aware of, but had no idea regarding the exposure issue. I would have never thought about it, since I have always metered TTL. I honestly have no recollection of how we set up when I used that Exacta rig I mentioned previously.

[dang]

Chris,
For drastic example, the Canon MPe 65mm 1X5X lens is rated at f/2.8. But when at 1:1, it's effective f-number is 5.6. What's amusing, the lens doesn't focus beyond life size. And since the dof is paper thin, most everyone stops down to f/16, giving an effective f-number of 96. if Canon marketed it as an f/5.6 lens, they'd probably lose a lot of sales. Even their (and others are similar) 100mm lenses rated at f/2.8 are effectively f/5.9 at life size, requiring a +2 exposure compensation without TTL metering.

I can't recall the formula for calculating effective f/stop, but I'll look it up again. There's a chart giving the effective stops for a 50 & 70mm when using tubes here: http://www.dangphoto.net Check the MPE 65 page.

Fun stuff.