Updated product pages: Why not pixel density ?

[bobn2]

Not only was the pixel density DPReview presented of questionable value, it was also wrong, based on assumptions how large e.g. a 1/2.3 inch sensor really was.

As soon as you can remove the lens you can get the actual size, either by the manufacturer giving it or by you measuring it.

Of course the manufacture gives it to you in a form, to what accuracy, I' don't know. It seems standard practice is to mark the lens with it's actual focal length and to market it in terms of its 35mm equivalent. By dividing one by the other you get the crop factor, by dividing 43.3 mm by that you get the sensor diagonal and then a little bit of Pythagoras and a knowledge of the aspect ratio of the sensor you gain the sensor dimensions. maybe not completely accurate, but probably accurate enough.
--
Bob

 

[Le Kilt]

The reasons DPR used it have been amply discussed above. You want to use it for a completely different reason.

Several reasons actually ;-)

If I understand you correctly you want to know a number for 'how many pixels on the duck'. That was at least the way someone tried to show it years ago: if you photograph a sitting duck. When shooting such a subject, a crop camera not only has the advantage of the smaller sensor [same focal length gives a smaller angle of view] but mostly [at least in the same generation] smaller pixels than the FF. This gives a more opportunity to crop if you use the result for screen display or small prints only.

Pixel density gets you information on 'cropability' only partially, as it can't take the final step into account.

I'm not quite sure of the point you're trying to make, but it's a question of whether a piece of information is useful or interesting, and the less obvious implications do need an understanding of other factors affecting image quality

As has been discussed before, the pixel density is not 'primary' information. There are two basic bits of information, the sensor size (x and y) and the pixel count (x and y), from these can be derived other things such as the pixel pitch and pixel density. The question is, if more than the two basic figures are to be given, which and why. There has been a case made for pixel pitch. Only one case has been made for pixel density, that is that it helps make 'reach' calculations. This is a bit bogus, because pixe frequency (reciprocal of pixel pitch) would be directly applicable to that need, so even that case is weak. So now it would seem if we are to have figures apart from the basic size and pixel count, that two (pitch and frequency) would be more usefult than 'density'. What the proponents of 'density' are having a hard time doing is actually coming up with some concrete reason why it's useful - w3e are given vague reasons or just 'I like it'.
--

Is the reason for it being withdrawn not due to its misuse?

I think it is an unwelcome reminder of a failed and misguided campaign.

Whatever, it was just a piece of information

Were you not also able to deduce pixel pitch and frequency from pixel density?

Not directly,

Really ? Can you tell me what you think pixel pitch is ?

you need to know the sensor size and/or pixel count as well, and if you have both those things you can calculate all of pixel pitch, pixel frequency and pixel density. The question is, why should pixel density have favoured status over pixel pitch and pixel frequency when both of those are more directly useful in concrete ways.

Ask dpreview, they put it there...

A piece of interesting information is taken away from the front page, and we're being told you shouldn't have been looking at that, I like this alternative that you don't get either...

I do apologise for "liking it", it's like an old friend who's been put down, sniff... :-(

And I can't see why you're getting emotional about it, since you've been unable to say what use it actually was to you.
--

Re-reading the whole thread and upgrading your sense of humour would help you there...

 

[Le Kilt]

No, there is nothing abstract about pixel density and it is exactly what I was looking for, if DPReview used it for a time there was a reason.

Hmmmm .... so when you buy milk, vegetable oil and other liquids you would want to have the density specified? Isnt volume and/or weight somewhat more useful? Except in very special cases of course.

Liquids ??? What a useless analogy, how about grains of sand on sandpaper...? ;-)

But worry not, you are free to look up and use whichever measurements you feel more comfortable with ;-)

No ... not really. I cannot look up whats not there. And now there is neither pixel density nor pixel pitch.

And actually I would not be bothered if any of those were added.

The main thing that bothered me regarding pixel density was that DPReview used it as a weapon in the anti mega pixel race crusade.

but hopefully some used it judiciously...

More pixels is in general good. Up to some limit where it simply is more than you can use or actually starts to degrade the image.

So more pixels can become bad...

--
Roland

support http://www.openraw.org/
(Sleeping - so the need to support it is even higher)

X3F tools : http://www.proxel.se/x3f.html

 

[bobn2]

The reasons DPR used it have been amply discussed above. You want to use it for a completely different reason.

Several reasons actually ;-)

If I understand you correctly you want to know a number for 'how many pixels on the duck'. That was at least the way someone tried to show it years ago: if you photograph a sitting duck. When shooting such a subject, a crop camera not only has the advantage of the smaller sensor [same focal length gives a smaller angle of view] but mostly [at least in the same generation] smaller pixels than the FF. This gives a more opportunity to crop if you use the result for screen display or small prints only.

Pixel density gets you information on 'cropability' only partially, as it can't take the final step into account.

I'm not quite sure of the point you're trying to make, but it's a question of whether a piece of information is useful or interesting, and the less obvious implications do need an understanding of other factors affecting image quality

As has been discussed before, the pixel density is not 'primary' information. There are two basic bits of information, the sensor size (x and y) and the pixel count (x and y), from these can be derived other things such as the pixel pitch and pixel density. The question is, if more than the two basic figures are to be given, which and why. There has been a case made for pixel pitch. Only one case has been made for pixel density, that is that it helps make 'reach' calculations. This is a bit bogus, because pixe frequency (reciprocal of pixel pitch) would be directly applicable to that need, so even that case is weak. So now it would seem if we are to have figures apart from the basic size and pixel count, that two (pitch and frequency) would be more usefult than 'density'. What the proponents of 'density' are having a hard time doing is actually coming up with some concrete reason why it's useful - w3e are given vague reasons or just 'I like it'.
--

Is the reason for it being withdrawn not due to its misuse?

I think it is an unwelcome reminder of a failed and misguided campaign.

Whatever, it was just a piece of information

Loaded information, intended to carry a message. That is not in doubt, the agenda was admitted.

Were you not also able to deduce pixel pitch and frequency from pixel density?

Not directly,

Really ? Can you tell me what you think pixel pitch is ?

Tell me how you work out the pixel pitch of a D1x from the pixel density.

you need to know the sensor size and/or pixel count as well, and if you have both those things you can calculate all of pixel pitch, pixel frequency and pixel density. The question is, why should pixel density have favoured status over pixel pitch and pixel frequency when both of those are more directly useful in concrete ways.

Ask dpreview, they put it there...

We know why they put it there:

'at least half of the reason for doing this [ publishing the pixel density ] is to 'expose' or 'put pressure' on the manufacturers to think about the terrible tradeoffs that the continuing megapixel race (mostly in compact cameras) are having on image quality.'
http://forums.dpreview.com/forums/read.asp?forum=1018&message=38332096

A piece of interesting information is taken away from the front page, and we're being told you shouldn't have been looking at that, I like this alternative that you don't get either...

I do apologise for "liking it", it's like an old friend who's been put down, sniff... :-(

And I can't see why you're getting emotional about it, since you've been unable to say what use it actually was to you.
--

Re-reading the whole thread and upgrading your sense of humour would help you there...

I think you'll find my sense of humour is in good order, unless you think I should just be laughing at your laughable opinions.
--
Bob

 

[robert1955]

My poijnt is that I'm trying to find out what your point is in wanting that number, a question which has been ased several times and you take some pais to avoid answering

If I understand you correctly you want to know a number for 'how many pixels on the duck'. That was at least the way someone tried to show it years ago: if you photograph a sitting duck. When shooting such a subject, a crop camera not only has the advantage of the smaller sensor [same focal length gives a smaller angle of view] but mostly [at least in the same generation] smaller pixels than the FF. This gives a more opportunity to crop if you use the result for screen display or small prints only.

Pixel density gets you information on 'cropability' only partially, as it can't take the final step into account.

I'm not quite sure of the point you're trying to make, but it's a question of whether a piece of information is useful or interesting, and the less obvious implications do need an understanding of other factors affecting image quality

So tell, if what I wrote is not what you want to know, what is?

 

[Le Kilt]

The reasons DPR used it have been amply discussed above. You want to use it for a completely different reason.

Several reasons actually ;-)

If I understand you correctly you want to know a number for 'how many pixels on the duck'. That was at least the way someone tried to show it years ago: if you photograph a sitting duck. When shooting such a subject, a crop camera not only has the advantage of the smaller sensor [same focal length gives a smaller angle of view] but mostly [at least in the same generation] smaller pixels than the FF. This gives a more opportunity to crop if you use the result for screen display or small prints only.

Pixel density gets you information on 'cropability' only partially, as it can't take the final step into account.

I'm not quite sure of the point you're trying to make, but it's a question of whether a piece of information is useful or interesting, and the less obvious implications do need an understanding of other factors affecting image quality

As has been discussed before, the pixel density is not 'primary' information. There are two basic bits of information, the sensor size (x and y) and the pixel count (x and y), from these can be derived other things such as the pixel pitch and pixel density. The question is, if more than the two basic figures are to be given, which and why. There has been a case made for pixel pitch. Only one case has been made for pixel density, that is that it helps make 'reach' calculations. This is a bit bogus, because pixe frequency (reciprocal of pixel pitch) would be directly applicable to that need, so even that case is weak. So now it would seem if we are to have figures apart from the basic size and pixel count, that two (pitch and frequency) would be more usefult than 'density'. What the proponents of 'density' are having a hard time doing is actually coming up with some concrete reason why it's useful - w3e are given vague reasons or just 'I like it'.
--

Is the reason for it being withdrawn not due to its misuse?

I think it is an unwelcome reminder of a failed and misguided campaign.

Whatever, it was just a piece of information

Loaded information, intended to carry a message. That is not in doubt, the agenda was admitted.

Were you not also able to deduce pixel pitch and frequency from pixel density?

Not directly,

Really ? Can you tell me what you think pixel pitch is ?

Tell me how you work out the pixel pitch of a D1x from the pixel density.

You can't tell me what you think pixel pitch is ?

you need to know the sensor size and/or pixel count as well, and if you have both those things you can calculate all of pixel pitch, pixel frequency and pixel density. The question is, why should pixel density have favoured status over pixel pitch and pixel frequency when both of those are more directly useful in concrete ways.

Ask dpreview, they put it there...

We know why they put it there:

'at least half of the reason for doing this [ publishing the pixel density ] is to 'expose' or 'put pressure' on the manufacturers to think about the terrible tradeoffs that the continuing megapixel race (mostly in compact cameras) are having on image quality.'
http://forums.dpreview.com/forums/read.asp?forum=1018&message=38332096

A piece of interesting information is taken away from the front page, and we're being told you shouldn't have been looking at that, I like this alternative that you don't get either...

I do apologise for "liking it", it's like an old friend who's been put down, sniff... :-(

And I can't see why you're getting emotional about it, since you've been unable to say what use it actually was to you.
--

Re-reading the whole thread and upgrading your sense of humour would help you there...

I think you'll find my sense of humour is in good order, unless you think I should just be laughing at your laughable opinions.
--

Obviously, should I have an opinion differing from yours it will be laughable...
Now, about your idea of what pixel pitch is...

 

[Le Kilt]

My poijnt is that I'm trying to find out what your point is in wanting that number, a question which has been ased several times and you take some pais to avoid answering

The point was that that was the info that dpreview put on the 'front page', making it easy to compare it across different cameras with same size sensors or different size sensors.

You could derive some info from that number, and compare it at a glance across cameras.

Many think there are more suitable numbers for their considerations, and that's fine, really, but that was what was available.

It it but one of the many elements affecting image quality, and using it without a good knowledge of other elements could be very misleading. It is this last point that some have addressed better than I would or will.

If I understand you correctly you want to know a number for 'how many pixels on the duck'. That was at least the way someone tried to show it years ago: if you photograph a sitting duck. When shooting such a subject, a crop camera not only has the advantage of the smaller sensor [same focal length gives a smaller angle of view] but mostly [at least in the same generation] smaller pixels than the FF. This gives a more opportunity to crop if you use the result for screen display or small prints only.

Pixel density gets you information on 'cropability' only partially, as it can't take the final step into account.

I'm not quite sure of the point you're trying to make, but it's a question of whether a piece of information is useful or interesting, and the less obvious implications do need an understanding of other factors affecting image quality

So tell, if what I wrote is not what you want to know, what is?

Nothing, I didn't ask you for any info, but thanks anyway