Nikon D300 70/300 VR lens question

[ISProf]

I'm making the change from point-and-shoot, and I've decided on this setup. I'm looking for something I can take on hikes and use on occasion without a tripod. I need write and focus speed and low light capability, hence this decision.

My question is how small an object can I expect to use to fill the frame from, say, 50 feet? House? Horse? Dog?

Thanks for the info.

[NHL]

You can fill the frame @ 300mm with a Dachshund at 50 feet...

[ISProf]

Exactly what I wanted to know. I should be in good shape to capture my basset hounds working, then! But, what if I wanted to capture a field mouse? What lens would you recommend?

[Bob Nichol]

You would need to get in to about 6 feet to fill the frame with a field mouse with a 300mm lens on a Nikon DX body.

A rough test of my Nikkor 70-300mm VR lens at 300mm on a Nikon D70s give me about 27 inches horizontal (widest) field of view at 30 feet in the house. Sorry, the weather was too miserable to go outside to get further!

Tamron has a dandy lens simulator at http://www.tamron.com/lenses/learnin...comparison.php that will give you an idea what to expect.

To get good results at those focal lengths you will need a solid support. VR helps in bright light but you still need shutter speed to stop action.

[NHL]

ISProf wrote:

... But, what if I wanted to capture a field mouse? What lens would you recommend?

At this point it becomes academic as you'll run into two issues:
1. How much do you want to spend?
2. Are you willing to put up with the weight?

I use an "inexpensive" Bigma 50-500mm for birding which the subject is about the size of your field mouse from a distance: http://www.pbase.com/nhl/sigma_50_500

However Sigma has just announced a 150-500mm with OS if you prefer VR. Nikon does have a fantastic 200-400 VR (about the same focal lenght as your old FZ10), but for that $ I rather shoot with my EF 500 f/4L (which you can also link to from the above URL)

[ISProf]

Very cool site. Makes me really wish I could handle a bigger lens.

[ISProf]

Two very good questions. Cost is not as much of an issue as weight. I know I can't have it all so I'm willing to get the best lens for my situation (mostly wildlife/dogs when trekking in different areas) but I can't handle too much weight. The camera is about 2 lbs - I would want to keep the lens less than 3 pounds (the 70-300 is less than 2).

[NHL]

ISProf wrote:

The camera is about 2 lbs - I would want to keep the lens less than 3 pounds (the 70-300 is less than 2).

Well the $1000 50-500 Bigma is about 3.96 lbs...
and the $5000 200-400 Nikkor VR is about 7.2lbs but you can use it with a 1.4xTC

The $1300 Nikon AFS 300 f/4 is probably closest in weight to what you're looking for @ 3.1lbs, but its not very different from your 70-300VR; However, you can augment it into a 420mm f/5.6 by adding a 1.4x teleconverter (which also add some weight)

-> which is why I said you need to pick your battle plan carefully (i.e. weight and cost)

[NHL]

Actually there are two other lenses under 3lbs, but they don't have the AFS:
The $800 Tamron 200-500: http://accessories.us.dell.com/sna/p...amp;lid=627063
... and the the $1600 Nikkon 80-400 VR

[Telecorder]

Distance to subject, subject size and IQ of the lens are all inter-related. -- The first two correlate to determining the long end needs and the latter is strongly related to cost.

Mothman13 did a chart for a Nikon D80 with a 1.5X crop Factor for different FOV image sizes (18mm - 600mm)... Look at the vertical height of the field of view at each subject distance.

http://www.pbase.com/mothman13/image/74511515 (5 - 30 feet)
http://www.pbase.com/mothman13/image/74511517 (35 - 60 feet)

Evaluate your intended subjects' sizes in light of his FOV chart above/below.... A perched Bald Eagle stands about ~24" tall so it would fill ~one-third of the vertical field of view of a 500mm lens if the subject was at ~200' distant (FOV ~72"-see below). In my experience, IQ starts to take a hit when an image is cropped more than 1/3 - 1/2 of the original FOV. Less cropping usually equates to more detail/better IQ of a properly exposed image.

Using my D50/Bigma, I've derived the additional following relationship...
Subject Distance -- ~Vertical FOV (assuming 2,000 vertical pixels)
50-ft -- 20"
100-ft -- 40"
200-ft -- 72"
300-ft -- 110"
400-ft -- 140"
500-ft -- 175"
600-ft -- 210"
What this all means is that the distance to the subject and subject size will also play a large part in just how detailed and sharp an image will be.

From Mothman's chart, at 200mm and 60' subject distance, the vertical FOV is ~4.6'. Using the rule of thumb that IQ degrades as the crop increases, a frame filling subject max size of 1/2 x 4.6' = 2.3' vertical; at 500mm this vertical frame filling FOV is ~1.8'x 1/2 = 0.9' (~11-inches)

In the end, I think one will be better served to also understand the issues of subject size/distance to subject/crop amount when evaluating ability of a lens to obtain the best IQ, detail and sharpness.

For ~$450-500, the 70-300 VR lens is a pretty walk-about good system. For 'serious reach' of small and/or distant wild life, 500-mm will be where you need to be...



I posted an extensive list of links to various long reach Nikon-mount lens alternatives that may be of interest at--

http://www.dslrgeeks.com/forum/showt...=2726#post2726