| Joined: | Mon Apr 2nd, 2012 |
| Location: | South Lakeland, UK |
| Posts: | 4066 |
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However, In order to benefit from the very highest resolution sensors, modern glass IS needed. The ultra high resolving power of the modern top end lenses which have been designed for digital are needed to get the full benefit from the modern high resolution sensors.
Rich mentions optimised for digital; the biggest optical difference between film and sensor is that the sensor usually has two thin sheets of glass in front of the sensor, the Low-Pass filter and a clear protective glass which is bonded to the sensor body which seals and protects the actual sensor photocells. Those two sheets of glass have an effect on the light passing from the rear element of your lens to the sensor photocells. Modern (optimised) lenses are designed to work with these extra layers of glass in front of the sensor, they do affect the light path, if only slightly.
With DX bodies and old, therefore full frame 35mm film lenses the sensor is only recording the centre 'sweet spot' of the image circle. Most lenses perform well in the centre DX area.
As for the exposure issues using non coupled, non chipped lenses, the histogram is your best friend here, I guess a manual exposure, make a test exposure and look at the histogram. I adjust the exposure untii the image data is just reaching the right hand (white) side. That should give you your best exposure.
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Robert.