Does A Lens Mount Adaptor Act Like A Extension Tube?
 

Just got a second hand Sigma 800mm, Nikon mount , to go with a GH4. I video birds in the main. Online blog stuff goes on about need for extension tubes for close up shots of small birds given the lens's limited minimum focussing distance.

I use (have to) a lens adaptor , mine's a Novoflex Nikon to MFT one. Given that this extends the distance between the lens and the camera's focal plane have I in fact got my extension tube?

Ron

Re: Does A Lens Mount Adaptor Act Like A Extension Tube?
 

No it doesn't. It takes up the space that would otherwise be used for the normal mount + camera body to provide the standard lens mount to sensor distance. You can add tubes between the mount and lens to gain a little shorter close focus distance.

Re: Does A Lens Mount Adaptor Act Like A Extension Tube?
 

If your Sigma lens and Novoflex adapter combination still focuses to infinity with your GH4 you do NOT have an extension tube. An extension tube will let you focus closer at the expense of your infinity setting.

If you are interested in working closer I could provide you with a formula to calculate the length required. Another way of getting closer is use a supplementary close-up lens but the same limitation applies to the infinity setting.

Re: Does A Lens Mount Adaptor Act Like A Extension Tube?
 

Thanks Jim and Alastair. I can focus to infinity with the adaptor attached, "past it" as well as the focussing ring can continue to be turned after infinity is reached.

Tried the lens "close" yesterday and with the GH4 2.3X 4K crop I get more than enough magnification on small birds fairly close.


Ron

Re: Does A Lens Mount Adaptor Act Like A Extension Tube?
 

Can you show us some samples Ron, I am interested in getting a Metabones GH4 - Nikon adapter so I can use my collection of Nikon lenses with the camera

Re: Does A Lens Mount Adaptor Act Like A Extension Tube?
 

I'd love to see a sample too. I have an 800 Nikkor and would like to see what your image quality looks like on that camera.

Re: Does A Lens Mount Adaptor Act Like A Extension Tube?
 

Here's a video with my 800 Sigma . Not Nikon, don't have that sort of cash but pleased with the Siggy.



Ron

ps this was with a Novoflex adaptor but I also have the Metabones which I use with my Nikkor 80-400.

Do not need the aperture selection facility, which both adaptors possess, for the Sigma which has an aperture ring unlike the Nikkor.

Re: Does A Lens Mount Adaptor Act Like A Extension Tube?
 

The Swans are truly wild birds by the way, the much rarer Bewick's, with more black on their bills are from Russia, the bigger Whooper's, yellower bills, are from Iceland.

If I'd got out of my Land Rover (I use a short tripod and Sachtler DV6 head placed over where the front passenger seat should be) the Swans would be off. Those nearest probably taking to flight, the rest walking quickly away across the field.

A race of the Bewick's (Whistling Swan) occurs in N America as does a close relative of the Whooper (Trumpeter Swan).

Ron

Re: Does A Lens Mount Adaptor Act Like A Extension Tube?
 

And here's another YouTube video via a GH4 at 96fps slo mo with the Nikkor 80-400 AF-S.

Connected via a Novoflex adaptor but I think the Metabones better with these aperture ringless lenses as the Meta aperture ring is easier to use.

Metabones cheaper as well. I wouldn't touch any of the really cheap adaptors with a bargepole.



ps muzak YT's, not mine, and stops too soon

Re: Does A Lens Mount Adaptor Act Like A Extension Tube?
 

These upped to YouTube straight of the SD cards via my iMac and Mpeg Streamclip. Camera settings "flat".

Originals look better, particularly 4K on a 4K monitor.

One reason for getting the big Sigma (and it is a lump) is being able to shoot at long range without the image deterioration you get between 4K/UHD and 1080p if you use the "Extra Tele Facility" on the GH4.

ETC on my old (and good) GH3s wasn't too bad but of course all at 1080p.

Ron

Re: Does A Lens Mount Adaptor Act Like A Extension Tube?
 

Those look pretty steady for the narrow field of view you have. Thanks for posting those. My 800 Nikkor is an older manual focus f5.6 version. I think it weighs about 16 lbs.

Re: Does A Lens Mount Adaptor Act Like A Extension Tube?
 

Ronald ,

I like both the videos, your pan skills are amazing.

Jim
I had a 800 Nikon manual focus, it's one of the best lens to shoot birds or other wildlife, I am cursing myself for selling it few years back.

Vishal