CA
|
JB,
what you are experiencing is normal - many photographers who upgraded from 12MP Nikon bodies to 18MP D7k (and also many in the Canon land one/two years ago) had to go through the same adjustment period.
Your frustration of mushy pictures most likely stems from two different sources, and tuning one will not even out the other. However, both sources of mushy pictures root in the new sensor technology.
Let me explain. The DX sensor, compared to an FX sensor is smaller in physical size. To put the *same* amount of megapixels (say 12MP like in D3 vs D300s) on the sensor, designers can go two different routes: a) make each individual sensel (pixel) smaller, and b) make the gap between two adjacent sensels smaller - both resulting in more sensels per area.
In order to cram the 18MP on the D7k sensor, Nikon/Sony most likely went with a combination of the above (making gaps smaller, making individual sensels smaller) by the use of micro-lenses on top of the sensels to bundle light. Regardless, the specifications state that the D7k has one of the smallest pixel-pitches seen in DSLR today. This has a three-fold effect on your photography:
First, there is your camera lens. Without doubt, the high resolution and small pixel pitch will pronounce any shortcomings of your current lenses - shortcomings that do not ever show up on your 12MP bodies. The DX sensor sees only a highly magnified part of the center of the lens. As an analogy think about looking at your computer monitor close up with a magnification glass: the before very sharp edges dissolve into mushy different coloured dots. Some of the existing Nikon lenses are not up to the task, and I doubt that many of the third-party lenses are. Yes, there is the high resolution D3x body and many lenses work perfectly fine, but again, since that is an FX camera, both pixel size and pixel pitch are still higher than what you see in the D7k!
Second, there is your camera technique. With the D7k, it is very hard to follow the old 'rule of thumb' of shutter speed = 1/focal length. I have recently had an email conversation with a senior member of this forum who had gone through the same adjustment period and picked his brains and one thing that had the biggest impact on my image quality was *high shutter speed*. In fact, if you do the test - there even is a perceptible blur due to mirror slap alone, if you set the camera on tripod and use a remote release, then take a picture with and without exposure delay mode on, and compare. If you must handhold the camera, a shutter speed of at least 1 / (2*equivalent focal length) is advisable. The faster, the better - if you go over 1/500th make sure you turn off the VR mechanism. Also, the D7k sensor seems to be overly sensitive to the shake of the VR, I've heard numerous reports so far that lenses with VR off produced sharper images on the D7k. In summary, putting the camera on a sturdy tripod or monopod, using a high shutter speed and leaving VR at home has made a significant impact in my images!
Third, there is sharpening. Images from the D7k require a fair amount of input sharpening due to the rather aggressive AA filter that sits on top of the sensor. In ACR, I found that about 60 sharpening, 0.8 radius, 40 detail and 20 masking produces a fairly usable starting point. Once you have your image in your desired output size (e.g., a 8x10 or a 720px web image) you need to apply output sharpening. USM to luminance work quite well in defining edges and bringing out the detail.
In comparison to all the bodies I have used so far (Canon XTi, Xsi, 40D, 50D, 60D, 5D, 5DII / Nikon D70, D90, D3, D700, D7000) the D7000 is the most unforgiving camera. The main reason I enjoy my D700 so much is that you can fire handhold and not worry - the pictures will come out fine. The D7k on the other hand requires quite a strict shooting regime or you will end up with results that are far below what the camera is able to achieve. And to be honest: the D7k is indeed able to produce higher detailed pictures than any other Nikon (apart from the D3x) - you just have to work for it!
Cheers,
Nic
P.S.: Here is one from when I finally figure out how to handle long lenses on a D7k. Click on the image to see the actual size image:
|
