[quote name='Brightcolours' timestamp='1323692168' post='13651']
Why do you have the idea that cropping via optics is not comparable to cropping via a smaller sensor, or indeed, cropping on the computer? Pretty odd.
Lets just focus on your cropping in photoshop for a minute.
Make a duplicate of an image. Crop to lets say 50% the duplicate.
Now count the lines per image height.
Guess which image has the higher resolution?
About optical cropping (TC). A lens has only a finite ability to resolve. Suppose it has a maximum, even, resolving power of "100" (in some fictive unit). Now, with a 2x TC, we only use the center part of the lens, which would be able to resolve "50".
That "50" will be distributed over the entire image, where before the total "100" was distributed.
Evidently, the image with TC has a lower resolution.
On to "cropping" with a smaller sensor.
Same lens can apparently resolve "100" on, lets say, a FF 135 format sensor format. Now we crop the projected image to half. Only "50" remains.
Now compare the FF image to the cropped image. Guess which one will have a higher resolution?
It does not matter where of how you crop. Whether it is via the sensor, via extra optics, or on a computer after image capture. It will always lead to the same which is less lines per image height resolved.
[/quote]
Less lines per total image (as some are cropped away) or less lines per, say, square cm. of image? You have me confused there.
Re: the Olympus 45mm lens that started this whole discussion, it looks very good. I don't find the Photozone review all that contradictory to the Lenstip and SLRGear evaluations. It seldom is the case anyways despite the very different presentation of results.
Now, I'd love to see the [url="http://www.slrgear.com/reviews/showproduct.php/product/1439/cat/68"]25[/url] reviewed. The 12, 25 and 45 make a kind of a holy trinity in the µ4/3 land. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />
Why do you have the idea that cropping via optics is not comparable to cropping via a smaller sensor, or indeed, cropping on the computer? Pretty odd.
Lets just focus on your cropping in photoshop for a minute.
Make a duplicate of an image. Crop to lets say 50% the duplicate.
Now count the lines per image height.
Guess which image has the higher resolution?
About optical cropping (TC). A lens has only a finite ability to resolve. Suppose it has a maximum, even, resolving power of "100" (in some fictive unit). Now, with a 2x TC, we only use the center part of the lens, which would be able to resolve "50".
That "50" will be distributed over the entire image, where before the total "100" was distributed.
Evidently, the image with TC has a lower resolution.
On to "cropping" with a smaller sensor.
Same lens can apparently resolve "100" on, lets say, a FF 135 format sensor format. Now we crop the projected image to half. Only "50" remains.
Now compare the FF image to the cropped image. Guess which one will have a higher resolution?
It does not matter where of how you crop. Whether it is via the sensor, via extra optics, or on a computer after image capture. It will always lead to the same which is less lines per image height resolved.
[/quote]
Less lines per total image (as some are cropped away) or less lines per, say, square cm. of image? You have me confused there.
Re: the Olympus 45mm lens that started this whole discussion, it looks very good. I don't find the Photozone review all that contradictory to the Lenstip and SLRGear evaluations. It seldom is the case anyways despite the very different presentation of results.
Now, I'd love to see the [url="http://www.slrgear.com/reviews/showproduct.php/product/1439/cat/68"]25[/url] reviewed. The 12, 25 and 45 make a kind of a holy trinity in the µ4/3 land. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />