Focal length 35mm equivalent, but not F-stop?

Started Jul 24, 2014 | Discussions thread
bobn2 Forum Pro • Posts: 63,564
Re: Focal length 35mm equivalent, but not F-stop?

Tim Tucker wrote:

bobn2 wrote:

Beachcomber Joe wrote:

bobn2 wrote:

Beachcomber Joe wrote:

The total light will decrease but not the light per square mm of area. Since the amount of light falling on a specific area of the sensor remains the same the exposure remains the same. A lot of the technobabble you read hear is about total light. Total light can be ignored. What matters from a photographic standpoint is the amount of light per square mm hitting the sensor.

Completely wrong. What matters is the total number of photons captured. Differences in exposure can always be compensated by simply changing the relationship between exposure and output grey scale. The total light locks in a noise pattern in the image, which can't be altered apart from noise reduction, which will usually lose you image detail. Those wishing to maximise image quality deal in total light. Of course, if you stick to one sensor size, there is no difference between total light and exposure.

Some people may not have known what I meant by the term technobabble. Thank you for providing such an excellent example.

Technobabble it might be, but it is true technobabble, and you have no way of refuting it. So, when you 'Total light can be ignored. What matters from a photographic standpoint is the amount of light per square mm hitting the sensor.' you're still 100% wrong. Choose to call what you're incapable of understanding 'technobabble' if you like, it doesn't make you any less wrong.

I'm following this with interest, and learning some useful bits and bobs, such as how sensors work.

But I am a bit perplexed as to how "total light" and "highest image quality" relate to good image. In the 20th century film produced fantastic images, even early digital cameras produced fantastic images. In fact some of the images produced are still fantastic, so if you used the same cameras could you not produce fantastic images today?

What matters from a photographic standpoint is the image you produce. And isn't there an argument that working within the limitations of your media produces the creativity and the strength of the image?

Of course, a good artist knows her medium and uses it to the best effectiveness. That is why matters like 'equivalence' are important for those that truly want to know their medium and how to use it. It also matters in selecting ones equipment, for there's no point spending the extra money of a 36MP FF camera if you're never going to use it in a situation where it gives you a better result than a 1/2.4" compact.

So, on your point about 'fantastic images', of course there is a valid argument that all modern films and digital camera produce images as fantastic as anyone could want, but that doesn't stop people buying better, and this web site is all about people buying better.

So, how does 'total light' relate to 'highest image quality? Simply because it tells you, so far as your operation of the camera  controls are concerned, how much noise or grain (depending on digital or film) will be in the image. And in the end, all else being equal, noise or grain is the major metric of image quality.

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