I used the D90 and XSi as those were the cameras mentioned by the OP. I have no idea what the average inaccuracy is across the market, but it doesn't matter, the fact that differences exist means that it's hard to make direct comparisons between models.
Well from the graph you can see that the true sensitivity is around 150.
If it interests you that much, and makes that big of a difference, it's quite easy actually. Just compare the two models. My point is that there is a standard in place, and generally speaking it gives you a pretty good idea of what your ISO sensitivity is. And if you are going to forgo the purchase of a certain camera because it has ISO200 as a base ISO, especially considering there are ND filters available for use, you are being a bit silly. Even if there is a slight variance in the ISO ratings.
If you want to be really accurate, I think it is closer to 160-170, but whose counting?
Well, I don't quite know what your point is. I agree that ND filters are useful and necessary in some situations. But I was responding on the subject of ISO equivalency between cameras.
True, but their performance can be objectively measured. In some cases this is relevant. For example if using an external incident light meter, it's helpful to know the actual sensitivity at a given nominal ISO.
It's unlikely one would ever notice that the actual exposure of a certain ISO on one camera is different than the exposure of the same ISO on another camera, especially with TTL metering. My point is simply that there are differences, nothing more.
We've ascertained that it does have mirror lock up. See page 1 of the preview under Nikon D7000 and Nikon D90: Key differences:
"Really accurate"? ;-)If it interests you that much, and makes that big of a difference, it's quite easy actually. Just compare the two models. My point is that there is a standard in place, and generally speaking it gives you a pretty good idea of what your ISO sensitivity is. And if you are going to forgo the purchase of a certain camera because it has ISO200 as a base ISO, especially considering there are ND filters available for use, you are being a bit silly. Even if there is a slight variance in the ISO ratings.
If you want to be really accurate, I think it is closer to 160-170, but whose counting?
--"Really accurate"? ;-)If it interests you that much, and makes that big of a difference, it's quite easy actually. Just compare the two models. My point is that there is a standard in place, and generally speaking it gives you a pretty good idea of what your ISO sensitivity is. And if you are going to forgo the purchase of a certain camera because it has ISO200 as a base ISO, especially considering there are ND filters available for use, you are being a bit silly. Even if there is a slight variance in the ISO ratings.
If you want to be really accurate, I think it is closer to 160-170, but whose counting?
If you hover your mouse over the ISO 200 dot on the graph for the D90, it shows "Measured ISO : 145", and "Manufacturer ISO : 200".
The 450D shows "Measured ISO : 151", and "Manufacturer ISO : 200".
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Patco
A photograph is more than a bunch of pixels
Its a true MLU. Nikon listed it in their brochure:
I actually visited Nikon site to read the brochure and found the same piece of information but wasn't sure it really means MLU. I thought the feature would be mentioned somewhere in the spec but did not and thus my question. Now it is all cleared up.
I look at this IOS thing from the basic definition - light sensibility. I believe even in digital form, ISO 100 means the same sensiblity level as film. Yes, it may be measured differently and the sensibility level may be roughly equivalent to but when one manufacture claims ISO 200, it certainly is "NOT" ISO 100. Otherwise it would have claimed ISO 100 capablity outright. Marketing is all about checklist items and would stretch thing as far as possible. When something is not mentioned, it simply means the product is nowhere near it. My reasoning is simply as that and makes a lot of sense to me.
