first post, questions about setup/Nikon 1x TV relay lens

optiphotmuser · Post by **optiphotmuser** » Wed Mar 23, 2011 4:19 pm

Hi guys, I've learned a ton from the forums but finally had a question I could not find the answer to.

I am wondering if anyone here has had experience using the Nikon 1x/16 TV relay lens with an older Optiphot M microscope (has a ~44mm photoport with a recessed 23 mm hole), BD Plan objectives (210mm), and a u4/3 camera.

How is the quality of this relay lens, especially compared to 1x relay lenses from Edmunds or Diagnostic Instruments? How does it compare to the Nikon CF PL series or the Olympus NFK relay lenses?

And lastly, what is the image distance of this relay lens?

This is the TV relay lens in question:
http://www.spachoptics.com/NIKON_1X_16_ ... y-lens.htm

Thanks in advance for any help!

Charles Krebs · Post by **Charles Krebs** » Wed Mar 23, 2011 6:04 pm

I've seen a fair number of these go on eBay for considerably less (in fact #320613848521 is a buy-it-now for $125).

I have avoided trying it out because being a 1X with a 16mm field number, I am pretty sure there is no way you could "cover" a DSLR sensor of any size. (But as I said, I've not tried it). Seems like it would only make sense with a 1" or smaller sensor.

fengqirst · Post by **fengqirst** » Mon Mar 28, 2011 3:54 pm

16mm is the field of the microscope,not the size of the CCD??

enricosavazzi · Post by **enricosavazzi** » Tue Mar 29, 2011 1:59 am

16 (mm) is the diameter of the field stop, which normally determines the field of view of the eyepiece before magnification (e.g. a 10x 21 eyepiece has a field stop of 21 mm and an apparent field of view through the eyepiece of 210 mm, as seen from a standard distance of 250 mm).

In this case, since the eyepiece magnification is 1x, it means that the eyepiece projects an image circle with a diameter of 16 mm. This corresponds to a complete coverage of a maximum rectangular sensor area of a little more than 12 mm by 9 mm. In other words, this eyepiece, used at the nominal magnification, will produce a substantial vignetting even on a Four Thirds sensor (which is 17.3 by 13 mm).

Normally, a 3.3x projection eyepiece is used with full-frame DSLRs, and 2.5x with APS-C DSLRs. If an eyepiece with an unusually wide field stop is used (and the objective produces a correspondingly wide aerial image), a 2x eyepiece might be enough for a full-frame sensor.

Charles Krebs · Post by **Charles Krebs** » Tue Mar 29, 2011 9:02 am

I hope I did not confuse the situation when I said "Seems like it would only make sense with a 1" or smaller sensor". I was referring to the odd nomenclature manufacturers use for sensor size. The imaging area of a 1" sensor actually measures about 12.8mm x 9.6 mm with a diagonal of 16mm. As such, this would likely be the largest sensor that this eyepiece would "cover". (But I am not aware of any consumer cameras that uses this size sensor and have removeable lenses).

enricosavazzi · Post by **enricosavazzi** » Tue Mar 29, 2011 10:10 am

Charles Krebs wrote:I hope I did not confuse the situation when I said "Seems like it would only make sense with a 1" or smaller sensor". I was referring to the odd nomenclature manufacturers use for sensor size. The imaging area of a 1" sensor actually measures about 12.8mm x 9.6 mm with a diagonal of 16mm. As such, this would likely be the largest sensor that this eyepiece would "cover". (But I am not aware of any consumer cameras that uses this size sensor and have removeable lenses).

As you noted, the nomenclature used to describe sensor sizes is singularly (and intentionally?) counterintuitive and misleading, ranging from the 1" you mentioned to Four Thirds (which seems to suggest a sensor larger than unity - and the unity a photographer is likely to have foremost in mind is a full frame sensor) to the 1/1.8" common in point-and-shoot cameras (which is actually about 1/23 the area of a full frame sensor, or 1/17 of a square inch).

Crop factors are somewhat more straightforward, but are used mainly with the APS-C family of sensor sizes, and sometimes Four Thirds sensors.

Admittedly, sensor sizes are not the only "muddied up" measurements in photography. Another that comes to mind is the power rating of studio strobes in Watt second (which is an objective measurement) and "effective Watt second" (which means nothing, is often used in advertisements and can be more than twice the actual Ws).

g4lab · Post by **g4lab** » Tue Mar 29, 2011 11:25 am

I think the original sensor nomenclature followed from the sizes of vidicon tubes that were in use prior to the advent of ccd and cmos sensors.

The first use of these was in video cameras and they were trying to communicate what size vidicon a sensor was equivalent to.

A One Inch vidicon does not have a one inch diameter sensing surface.

And the tubes came in larger and smaller sizes too.

kriscavok · Post by **kriscavok** » Sat Apr 06, 2013 5:24 am

Do you know "flange focal distance" or other hint to correctly use it with no Nikon microscope tube?
Regards!