Wednesday, December 5, 2012

Nikon V1 Lens comparison, 18.5mm vs 10-30mm

Here are some side-by-side testing results for the Nikon V1 using the Nikkor 10-30mm f/3.8-5.6 and Nikkor 18.5mm f/1.8.  This was performed using the Nikon V1 camera, Kowa 883 scope, and 25x LER eyepiece.

I printed out an ISO 12233 Resolution Chart, and set up the scope approximately 8 meters away.

The camera settings were set as follows for both lenses: ISO 100, Auto Focus, Aperture Priority Mode,  EV -.7 (this is where I usually have it – perhaps 0 would have been better, but at least it was the same for both lenses).  All images were taken using a 2 second timer.

First I used the 18.5mm lens.  With the lens wide open, the exposure time was 1/800 sec.

I switched to the 10-30mm lens, and tried to set it to exactly 18.5mm (looking at the EXIF data), but was only able to manage 18.2mm or 18.9mm – perhaps the lens zoom can only be set with a certain resolution.  In any case, I saw the same results for either 18.2 or 18.9mm, which resulted in an aperture of f/4.5For the same image the exposure time was 1/320 sec, or about 2.5 times slower than the 18.5mm lens.

I then zoomed to 30mm, where I sometimes shoot, resulting in an aperture of f/5.6 and exposure time of 1/200 sec.

After cropping in Photoshop Elements, the image histograms were fairly similar, with the 18.5mm image having a mean count of 85.7 with the 10-30mm image showing a mean count of 90.6 – the 10-30mm image is a bit brighter.

The images below are at 100% crop, 2400 x 1800 pixels.

18.5mm lens f/1.7 ISO 100 EV -.7 1/800 sec

10=30mm lens f/4.5 ISO 100 EV -.7 1/320 sec

Saturday, December 1, 2012

Nikkor 18.5mm f/1.8 Lens with the Nikon V1

Was excited yesterday when my lens arrived a day earlier than promised.  Unfortunately it was raining and nearly dark by then.  This morning I had a chance to play with it briefly, and the results look very promising.

I have been using the Nikkor 10-30mm lens, with a minimum f# of 3.5, but at the zoom level useful to the scope the minimum f# is usually about 5.0.  So the new lens, at f/1.8 potentially offers a huge improvement of about 3x or more in shutter speed improvement.

Another advantage of the new lens for some users is the smaller size, as the Nikon V1 with the 10-30mm lens is too big to be used with many of the point-and-shoot scope adapters out there.  I measured the protrusion of the 18.5mm lens from the front of the camera to be 36.1mm.  The 10-30mm lens has a protrusion of 58.1mm to 64.1mm, depending on the zoom (min protrusion is in the center of the zoom, with max protrusion at min and max zoom).  So switching to the 18.5mm lens means you can move the camera 22-28mm closer to the scope or roughly 1-1.3 inch.

I placed the lens on the camera and fitted it to my Kowa scope with the 25x LER eyepiece.  The lens snuggles right into the end of the eyepiece with no vignetting present - a perfect match.

There was a brief lifting in the weather, I was able to get outside and get a few shots in what generally would have been very poor conditions - cloudy on the verge of fog.  In that brief window, shooting at f/1.8 I had the luxury of setting the camera to ISO 400 while able to achieve reasonable shutter speeds.  With the 10-30mm lens I would most likely have thought "too dark out" and not even tried.

I first went to my go-to bird, the male Anna's Hummingbird that is often hanging around waiting to drive other birds away from "his" feeder.  He was very cooperative, as usual.  Before the weather closed in again, I also had a quick visit from a Yellow-rumped Warbler (Audobon's Warbler).  The bird photos below are unprocessed in any way, simply cropped at actual size ("100% crop", no resizing or resampling).

I think I am going to like this lens!

Nikkor 10-30mm lens (left) and 18.5mm f/1.8 lens (right)

  Nikon V1, Nikkor 18.5mm f/1.8 lens, fitting nicely into the Kowa 25x LER eyepiece.

 Anna's Hummingbird, f/1.8  ISO400  1/320 sec
  Anna's Hummingbird, f/1.8  ISO400  1/320 sec

Yellow-rumped Warbler (Audobon's Warbler), f/1.8  ISO400  1/125 sec
The fog had set in by the time this fellow arrived.