Need advise on Auto Extension Ring.

WideZoom · 19th July 2004

What are the respective differences between the following Auto Extension Ring, PK-11A;
PK-12; PK-13; PN-11 when attach to Nikkor AF 50mm f/1.8D Lens in terms of the following?

- Maximum Reproduction Ratio.
- Reduction in F-Stop.
- Changes in Focal Length.

Thanks
Regards.

mikerfns · 20th July 2004

According to the tables supplied by Nikon, when mated with the AF 50mm f/1.8

- Maximum Reproduction Ratio (at minimum focus).
PK-11A ... 1/3.3; PK-12 ... 1/2.4; PK-13 ... 1/1.5; PK-11A + PK-12 + PK-13 (49.5mm extension) ... 1/1.1

- Reduction in F-Stop (at minimum focus).
Exposure factors of: PK-11A ... 1.7; PK-12 ... 2; PK-13 ... 2.7; PK-11A + PK-12 + PK-13 (49.5mm extension) ... 4.2

- Changes in Focal Length.
None. Extension tubes do not change the focal length or angle of view. They reduce the minimum focusing distance by moving the lens away from the film plane.

I don't have a chart for the PN-11 (52.5mm extension), but the values above for the PK-11A + PK-12 + PK-13 combination (49.5mm extension) would be very close.

Mike

justarius · 20th July 2004

I'm not sure if you know this already but you will NOT get AF or any form of metering when using ANY of Nikon's extension tubes with the lower echolon cameras (eg F75, F80, D70). You will get centre weighted/spot metering (still no matrix except with the F4) only with the manual focus series of cameras, or the higher end pro-level cameras (F100, F5, D1/D2 series).

gooseberry · 20th July 2004

Yeah, if you want to get AF and metering, get the Kenko range of extension tubes.

WideZoom · 20th July 2004

Thanks Mikerfns, Justarius and gooseberry for your advise.

WideZoom · 21st July 2004

I understand that "Working Distance" is the distance between the front of the
lens and the subject. But what does "Closest Marked Focus Distance" or
"Minimum Focus Distance" means on Micro lens.

Taking for instance Nikkor AF Micro 105mm f/2.8D lens indicating "Working Distance"
as 136mm and "Closest Marked Focus Distance" as 314mm. Does it mean that the
lens would only achieve 1:1 reproduction at 136mm and the lens would be out of focus
at more than 314mm distance.

Pls advise as I'm very new to photography.

Thanks
Regards.

mikerfns · 21st July 2004

Originally Posted by WideZoom

Taking for instance Nikkor AF Micro 105mm f/2.8D lens indicating "Working Distance"
as 136mm and "Closest Marked Focus Distance" as 314mm. Does it mean that the
lens would only achieve 1:1 reproduction at 136mm and the lens would be out of focus
at more than 314mm distance.

The "minimum focus distance" or "closest marked focus distance" is the distance between the subject being photographed and the film plane at minimum focus. In other words it is basically the distance from the subject to the back of your camera. Focus distances marked on a lens are measured to the film plane, not the front of the lens.

The "working distance" is the distance from the subject to the front element of the lens in use.

In the example you quoted, to achieve a 1:1 reproduction ratio, the subject would be only 136mm from the front of the lens, but 314mm from the film plane.

Mike

WideZoom · 21st July 2004

Does it mean that if we move further than 314mm, reproduction would be less than 1:1 until at a distance where AF would no long be possible?
So what is this distance or could Micro lens focus at infinity?

novaD70 · 21st July 2004

Widezoom, I can see the 'blurness' in you - because this is exactly my problem now. No matter how I search the net, I am still no wise off - it seems that that qn I wanted is always not there. So I have decided to get one set to try - I cannot find any other way.

And I can almost predict that the folowing will happen after I got the ring:

1. Will be presently surprise that it can also do certain things that I haven't think of or I thought not possible
2. Will also be 'disappointed' to discover that 'huh, like that only"

21st July 2004

Buy and practise, practise, practise. The histograms are REALLY useful for checking your exposure!

If you have a flash, this will help, especially when using all the extension tubes together. Lose a lot of light this way.

mikerfns · 21st July 2004

Originally Posted by WideZoom

Does it mean that if we move further than 314mm, reproduction would be less than 1:1 ...

Yes. To achieve a exact life-size image on film with this lens (1:1 reproduction - for example a 20mm coin will produce an image 20mm in diameter on the film negative) the subject must be 314mm from the film plane.

Originally Posted by WideZoom

... until at a distance where AF would no long be possible?
So what is this distance or could Micro lens focus at infinity?

AF is possible at all distances. Nikon AF "Micro" lenses can autofocus at any distance from infinity to "minimum focusing distance". However, you will only achieve life size images at minimum focus.

Mike

justarius · 22nd July 2004

yup, Mike is correct.

Also, do note that with an extension tube attached, you will lose infinity focus, ie. you cannot focus to infinity with an extension tube. The focussing range is very limited, so don't be worried if you keep on getting blur pictures. Recommended way of focussing is to physically move in/out with the lens till you see a sharp picture.

19th July 2004	#1
WideZoom Member Join Date: Mar 2004 Location: Lavender Posts: 540	Need advise on Auto Extension Ring. What are the respective differences between the following Auto Extension Ring, PK-11A; PK-12; PK-13; PN-11 when attach to Nikkor AF 50mm f/1.8D Lens in terms of the following? - Maximum Reproduction Ratio. - Reduction in F-Stop. - Changes in Focal Length. Thanks Regards.

21st July 2004	#6
WideZoom Member Join Date: Mar 2004 Location: Lavender Posts: 540	Closest Marked Focus Distance ?? I understand that "Working Distance" is the distance between the front of the lens and the subject. But what does "Closest Marked Focus Distance" or "Minimum Focus Distance" means on Micro lens. Taking for instance Nikkor AF Micro 105mm f/2.8D lens indicating "Working Distance" as 136mm and "Closest Marked Focus Distance" as 314mm. Does it mean that the lens would only achieve 1:1 reproduction at 136mm and the lens would be out of focus at more than 314mm distance. Pls advise as I'm very new to photography. Thanks Regards.

20th July 2004	#2
mikerfns New Member Join Date: Dec 2003 Location: Nova Scotia, CANADA Posts: 29	According to the tables supplied by Nikon, when mated with the AF 50mm f/1.8 - Maximum Reproduction Ratio (at minimum focus). PK-11A ... 1/3.3; PK-12 ... 1/2.4; PK-13 ... 1/1.5; PK-11A + PK-12 + PK-13 (49.5mm extension) ... 1/1.1 - Reduction in F-Stop (at minimum focus). Exposure factors of: PK-11A ... 1.7; PK-12 ... 2; PK-13 ... 2.7; PK-11A + PK-12 + PK-13 (49.5mm extension) ... 4.2 - Changes in Focal Length. None. Extension tubes do not change the focal length or angle of view. They reduce the minimum focusing distance by moving the lens away from the film plane. I don't have a chart for the PN-11 (52.5mm extension), but the values above for the PK-11A + PK-12 + PK-13 combination (49.5mm extension) would be very close. Mike

20th July 2004	#3
justarius Member Join Date: Nov 2003 Location: Northeast Posts: 1,205	I'm not sure if you know this already but you will NOT get AF or any form of metering when using ANY of Nikon's extension tubes with the lower echolon cameras (eg F75, F80, D70). You will get centre weighted/spot metering (still no matrix except with the F4) only with the manual focus series of cameras, or the higher end pro-level cameras (F100, F5, D1/D2 series).

20th July 2004	#4
gooseberry Senior Member Join Date: Mar 2004 Location: Central West Posts: 1,937	Yeah, if you want to get AF and metering, get the Kenko range of extension tubes.

21st July 2004	#9
novaD70 Member Join Date: Jun 2004 Location: Jurong, Singapore Posts: 60	Widezoom, I can see the 'blurness' in you - because this is exactly my problem now. No matter how I search the net, I am still no wise off - it seems that that qn I wanted is always not there. So I have decided to get one set to try - I cannot find any other way. And I can almost predict that the folowing will happen after I got the ring: 1. Will be presently surprise that it can also do certain things that I haven't think of or I thought not possible 2. Will also be 'disappointed' to discover that 'huh, like that only"

21st July 2004	#10
Phildate Guests Posts: n/a	Buy and practise, practise, practise. The histograms are REALLY useful for checking your exposure! If you have a flash, this will help, especially when using all the extension tubes together. Lose a lot of light this way.

22nd July 2004	#12
justarius Member Join Date: Nov 2003 Location: Northeast Posts: 1,205	yup, Mike is correct. Also, do note that with an extension tube attached, you will lose infinity focus, ie. you cannot focus to infinity with an extension tube. The focussing range is very limited, so don't be worried if you keep on getting blur pictures. Recommended way of focussing is to physically move in/out with the lens till you see a sharp picture.