Trouble with Extension Tubes

[sashib]

I have a Nikon D3100 & I bought some extension tubes! They work fine only problem is I can't see through the viewfinder! Its like the lense cap is on!
Can anybody help me discover the problem?

 

[g13a]

This is a common with manual extension tubes.
Try it with a wider aperture,maybe f8 or f5.6,you will see the light coming while you won't be able to get depth of field required.

 

[480sparky]

Your tubes are probably el-cheapos that don't have the mechanical linkage between the body & lens. This linkage is what holds the aperture open until you actuate the shutter.

 

[Edsport]

Your tubes are probably el-cheapos that don't have the mechanical linkage between the body & lens. This linkage is what holds the aperture open until you actuate the shutter.

I don't think this is the problem, the ones without electrical contacts will give F/0 which lets in the most light possible but also the least depth of field...

 

[cgipson1]

What brand of extension tubes? The only ones most of us recommend are the Kenkos... they maintain full electronic and mechanical compatibility with the camera body and your lenses. There are cheap knock offs that some people say work ok. There are also really cheap tubes like Sparky mentioned.. that have no electical or mechanical compatibility. If you have those.. return them, or throw them away.. and get some Kenkos!

 

[morganza]

I have no experience with this, but i find this thread interesting. Posting because I'd like to see what action you will take and how effective it is or won't be.

 

[nmoody]

Highly recommend the kenko's, they work real well on my D3100

 

[480sparky]

Your tubes are probably el-cheapos that don't have the mechanical linkage between the body & lens. This linkage is what holds the aperture open until you actuate the shutter.

I don't think this is the problem, the ones without electrical contacts will give F/0 which lets in the most light possible but also the least depth of field...

The ones without any mechanical and electrical connections means the camera can't read any data from the lens, so it records a default f/0,......... and the aperture on the lens is stopped down to it's mechanical minimum, which will be something like f/22 or smaller.

Try mounting the tubes and a lens, then look into the lens itself... I gotta nickel says it's stopped all the way down.



I'd love to see a lens with a true f/0 capability.

 

[Edsport]

Your tubes are probably el-cheapos that don't have the mechanical linkage between the body & lens. This linkage is what holds the aperture open until you actuate the shutter.

I don't think this is the problem, the ones without electrical contacts will give F/0 which lets in the most light possible but also the least depth of field...

The ones without any mechanical and electrical connections means the camera can't read any data from the lens, so it records a default f/0,......... and the aperture on the lens is stopped down to it's mechanical minimum, which will be something like f/22 or smaller.

Try mounting the tubes and a lens, then look into the lens itself... I gotta nickel says it's stopped all the way down.



I'd love to see a lens with a true f/0 capability.

Yes i know F/0 is a false reading but the aperture won't be closed down to minimum, it's just the opposite and the aperture will be wide open.

A lens (whether using an extension tube or without) is always wide open until you press the shutter button or the DOF button. Maybe this is for canon only and nikon is different i have no idea. If nikon is different than you would be right...

 

[480sparky]

Yes i know F/0 is a false reading but the aperture won't be closed down to minimum, it's just the opposite and the aperture will be wide open.

A lens (whether using an extension tube or without) is always wide open until you press the shutter button or the DOF button. Maybe this is for canon only and nikon is different i have no idea. If nikon is different than you would be right...

Um.... the reason the lens is open is because it's mounted to your camera, and there's a mechanical link between the lens and the body. Remove the lens from the body, and there's nothing to hold the aperture open, so it closes to it's mechanical limit. Mount the same lens on a set of tubes that do not maintain this mechanical linkage, and the result is the same.... f/22 or f/32 or f/36, whatever the lens is made for.

Simple tests for you to try: Remove the lens from the body and look through it. Is it closed all the way down? That's because there's nothing to hold it opn.

Put the lens back on the body. Is it open? Hmmm. Must be the link on the camera holding it open.

Put one extension tube between the lens & body. Is the aperture open or closed? If it's open, then the tube has the mechanical link built into it. It it's closed, the tube doesn't have the link, and that's your problem.

 

[Edsport]

Yes i know F/0 is a false reading but the aperture won't be closed down to minimum, it's just the opposite and the aperture will be wide open.

A lens (whether using an extension tube or without) is always wide open until you press the shutter button or the DOF button. Maybe this is for canon only and nikon is different i have no idea. If nikon is different than you would be right...

Um.... the reason the lens is open is because it's mounted to your camera, and there's a mechanical link between the lens and the body. Remove the lens from the body, and there's nothing to hold the aperture open, so it closes to it's mechanical limit. Mount the same lens on a set of tubes that do not maintain this mechanical linkage, and the result is the same.... f/22 or f/32 or f/36, whatever the lens is made for.

Simple tests for you to try: Remove the lens from the body and look through it. Is it closed all the way down? That's because there's nothing to hold it opn.

Put the lens back on the body. Is it open? Hmmm. Must be the link on the camera holding it open.

Put one extension tube between the lens & body. Is the aperture open or closed? If it's open, then the tube has the mechanical link built into it. It it's closed, the tube doesn't have the link, and that's your problem.

I can only speak for canon and the lens is not closed down to it's limit. Turn your camera off and look through the eyepiece and everything is still just as bright as if the camera was turned on and if you think there is still a mechanical link that is holding the aperture open, unscrew the lens a little and look through the eyepiece and still everything is just as bright as if it was on the camera with the mechanical link which means the aperture is wide open...

 

[480sparky]

I can only speak for canon and the lens is not closed down to it's limit. Turn your camera off and look through the eyepiece and everything is still just as bright as if the camera was turned on and if you think there is still a mechanical link that is holding the aperture open, unscrew the lens a little and look through the eyepiece and still everything is just as bright as if it was on the camera with the mechanical link which means the aperture is wide open...

Silly me for thinking we're addressing Nikon, as this is in the Nikon subforum.

And yes, the aperture is still open when you look through the viewfinder (regardless of whether the camera is on or off)....... because the lens is still on the body and the link in the camera is still holding the aperture blades open.

When one removes a Nikon lens from a Nikon body, the aperture blades close. At least on F-mount lenses built since 1959.

 

[Hobbytog]

I've got a set of Kenko tubes that I use with the 600D and 100mm f2.8 macro. In the brief instructions that come with them the recommendation is to fit the tube to the camera and then the lens to the tube to ensure the correct connections are made.

 

[Edsport]

I can only speak for canon and the lens is not closed down to it's limit. Turn your camera off and look through the eyepiece and everything is still just as bright as if the camera was turned on and if you think there is still a mechanical link that is holding the aperture open, unscrew the lens a little and look through the eyepiece and still everything is just as bright as if it was on the camera with the mechanical link which means the aperture is wide open...

Silly me for thinking we're addressing Nikon, as this is in the Nikon subforum.

And yes, the aperture is still open when you look through the viewfinder (regardless of whether the camera is on or off)....... because the lens is still on the body and the link in the camera is still holding the aperture blades open.

When one removes a Nikon lens from a Nikon body, the aperture blades close. At least on F-mount lenses built since 1959.

The aperture remains open on a canon whether the lens is in contact with the camera or not but since i know nothing about the nikon lens then i'm assuming that it closes...

 

[cgipson1]

Sparky is dead on, 100% correct! Nikon lenses have thier apertures closed down when off the camera! So there, that's over! What Canon's do have nothing to do with the problem the OP is having, since he does have Nikon!