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Huh? Extension tubes...
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PostPosted: Sun Sep 19, 2021 3:21 am    Post subject: Huh? Extension tubes... Reply with quote

Kind of wondering about what I'm seeing offered used in camera shops.
Been seeing a bit of nikon PK-2's attached to long lenses- one on a 300mm nikkor, and another on a generic 200.
I most recently examined a nikon PK-3 on a 180 2.8 ED.
These lenses are all consignment sales, and the dealers are un-willing to separate the tubes from the lenses.

I know the PK-2's were packaged with the 55 micro nikkors, and it of course rubs me the wrong way.
I tried with my own 200 with my generic un-coupled tube set and still don't quite see the point of extending such long lenses.
With the 200 f4 nikkor, it works at about a meter and a half, and no where else.
I'm on apsc though- should check with one of the film camera's.
The extremely shallow depth of focus with such a set-up appears to be very difficult to work with.
Any one here using long lenses on an extension tube?
Kind of curious as to what this set-up would be used for...

-D.S.


PostPosted: Sun Sep 19, 2021 4:36 am    Post subject: Reply with quote

I have used a Topcor macro helical with their 500mm lens. That’s just a variable extension tube. It allowed me to get about 10 feet closer on the MFD. It was reduce from 26 feet to about 16 feet approximately. By no means was it considered macro though.

Not sure why your seller refuses to separate the two. Could it be to hide damage to the lens or bayonet?


PostPosted: Sun Sep 19, 2021 5:52 am    Post subject: Reply with quote

Consignment sales consist of as is/where is etc. on a fairly stringent basis.

I was tempted by the 180 2.8 ED, but it badly needed a CLA, and it's size is cumbersome to put it mildly...

I need to play with the tubes a bit more before the flowers all disappear for the year.

-D.S.


PostPosted: Sun Sep 19, 2021 6:59 am    Post subject: Reply with quote

I've used short tubes on several of my MFT telephotos, for things like butterflies they can be quite useful reducing MFD & still giving a reasonable focus range. A 10mm tube on a 300mm lens isn't too drastic a change Smile


PostPosted: Sun Sep 19, 2021 7:45 am    Post subject: Reply with quote

Blazer0ne wrote:
Not sure why your seller refuses to separate the two. Could it be to hide damage to the lens or bayonet?

It is possible.
Also, it's difficult to sell the tubes separately and most of the sellers don't want to bother with stashing them for years. Shouldn't be a problem with separating them for sale, though... unless the seller doesn't know that they can do that:
Browsing the Web you can sometimes bump into "Hama UV o-haze" lenses or something like that- only because someone found a lens in their closet, with a filter or teleconverter attached to it and thought it's the lens' name.


PostPosted: Sun Sep 19, 2021 2:16 pm    Post subject: Reply with quote

On a consignment sale, the dealer would have to contact the seller for permission to separate them.
I don't think either would be interested in doing so for the low return on selling something like an extension tube.
I'm guessing the tubes are added to increase the return a bit on selling the lens...

-D.S.


PostPosted: Mon Sep 20, 2021 8:49 pm    Post subject: Re: Huh? Extension tubes... Reply with quote

Doc Sharptail wrote:
Kind of wondering about what I'm seeing offered used in camera shops.
Been seeing a bit of nikon PK-2's attached to long lenses- one on a 300mm nikkor, and another on a generic 200.
I most recently examined a nikon PK-3 on a 180 2.8 ED.
These lenses are all consignment sales, and the dealers are un-willing to separate the tubes from the lenses.

I know the PK-2's were packaged with the 55 micro nikkors, and it of course rubs me the wrong way.
I tried with my own 200 with my generic un-coupled tube set and still don't quite see the point of extending such long lenses.
With the 200 f4 nikkor, it works at about a meter and a half, and no where else.
I'm on apsc though- should check with one of the film camera's.
The extremely shallow depth of focus with such a set-up appears to be very difficult to work with.
Any one here using long lenses on an extension tube?
Kind of curious as to what this set-up would be used for...

-D.S.

If you look at how most primes focus, they move the optics toward and away from the sensor/film plane, at its closest point is infinity focus, then as the optics are moved away the plane of focus moves from infinity toward the camera till you reach the lenses minimum focus distance (MFD).
Adding an extension tube to the lens shifts the previous focus range closer to the camera at the expense of infinity focus, so if a Tele lens focused from 2m to infinity it may focus from 0.75m to 5m with a tube installed, depth of field (DOF) will become much narrower due the closer focus.
Some use it for shooting portraits with longer lenses at a more comfortable shooting distance, others use tubes for more magnification, you can stack tubes to reach macro magnifications but you generally limit shooting options as you do so, many shooters prefer to shoot macros of critters with longer focal lengths so they don't have to get as close for the same amount of magnification. A 200 mm macro has a longer helicoid which is basically a variable tube.

As to why the shop doesn't want to remove the tube? It's not their lens if it's on consignment, but if you are serious about buying but want to test it without the tube before buying to make sure it can actually be removed and the lens has no issues, it's your right to test it before buying it, they are free to refuse to remove the tube before buying it and you are free to walk away, but that attitude doesn't sell the lens... Ask them if they would buy a used lens at market value without testing it, I'm willing to bet they wouldn't, at the very least they should contact the seller for permission to detach the tube for a possible buyer, if that's out of the question I'd shop elsewhere.


PostPosted: Mon Sep 20, 2021 9:10 pm    Post subject: Reply with quote

I got lucky with my PK auto tubes, they were on a body with no lens and the retailer was happy to take my money Wink
I went back a few days later and bought the body at a knock-down price 'cos there was no lens on it Wink
I'll use tubes with a 135mm on an APS-C body for a less distorted perspective whilst achieving reasonable magnification … good for flowers and the like in their natural environment. I know bellows are more flexible and have greater extension, but they're also more fragile "crawling around in the undergrowth".


PostPosted: Tue Sep 21, 2021 2:42 am    Post subject: Reply with quote

Thanks for the replies.
A lot to think about here.
My cheap little uncoupled 4 piece N.P.S kit is going to have to do for the next little while.
I am going to continue with this dealer. I've gotten quite a few price breaks from them.
Selling or not selling a low value item like an extension tube is not enough to sever a successful relationship such as ours.
I asked, and they declined...

-D.S.


PostPosted: Tue Sep 21, 2021 8:26 am    Post subject: Reply with quote

kypfer wrote:
I got lucky with my PK auto tubes, they were on a body with no lens and the retailer was happy to take my money Wink
I went back a few days later and bought the body at a knock-down price 'cos there was no lens on it Wink
I'll use tubes with a 135mm on an APS-C body for a less distorted perspective whilst achieving reasonable magnification … good for flowers and the like in their natural environment. I know bellows are more flexible and have greater extension, but they're also more fragile "crawling around in the undergrowth".


How about during volcanic eruptions? Are you near that?