Jonny Boyd

Jonny Boyd

Joined on Sep 15, 2012

Jonny Boyd's recent activity

  • Well fairly obviously if the diffraction limit was at an intermediate f-stop (say f/6.3) then a lens which can't stop down to that exact aperture will in practice be limited at the next aperture ...
  • Who ever mentioned cross-system comparisons? Though the work I've done looks at sensor resolution without specifying sensor size. I'm baffled as to why you would need to say that when it has ...
  • To clarify, do you mean -d/dL ([log (R)] / R) where R = (1/L^2 + 1/S^2)^-1/2 ? If so, then I think it looks like this (though my calculus is admittedly rusty): If the threshold under certain ...
  • Yes. i just wanted to be careful with the definition to make at absolutely clear that there is no disagreement over facts like this. Close. 'The diffraction limit for a system occurs at the ...
  • Replied in Check your maths
    I don't have a maths degree, but I'm pretty sure you can't compare units with different dimensions, so asking if delta_w/w_p (dimensionless) is less than w_0 (length) is nonsensical.
  • Replied in Um...
    And what value does that comment add to the discussion? You asked for a more detailed consideration of factors such as visual acuity, viewing distance, image size and so on. I've had a go at doing ...
  • Replied in Um...
    As I've repeatedly explained, when diffraction produces a visible drop in resolution in situations where a lower resolution sensor wouldn't exhibit a visible drop in resolution, then diffraction ...
  • My definition comes at the end of this post. I wanted to put in some brief explanation first. Diffraction always limits the resolving power of a lens, even wide open, and the effect gets stronger ...
  • As I've said elsewhere, I'm not trying to quantify where resolution would visibly drop. I'm merely establishing that both the relative and absolute drop in resolution between apertures is less for ...
  • I don't know if you realise it, but when you've just spend a whole post pointing the finger and assigning blame, it sounds rather insincere to say at the very end that you have no problem with ...
  • So you say, but without ever articulating what exactly is wrong beyond you not liking the numbers which I plugged into the equation. Where exactly did I allegedly claim to think that? I've ...
  • In this post ( Re: Diffraction Limit Discussion Continuation ) I said: If we said that a resolution difference of 0.1% was the limit of perception, then for all practical purposes, peak resolution ...
  • And where exactly is that assumption? I am concerned with the general principle that lower resolution sensors experience lower relative and absolute drops in resolution than higher resolution ...
  • You seemed to be highly sceptical of everything I've previously posted. Then I don't understand why you kept disagreeing with me. I meant pixel count, yes. How exactly is it 'ill-informed'? It's a ...
  • If you assume that pixel count makes no difference and make no attempt to investigate whether pixel count makes a difference, how can you authoritatively say that pixel count makes no difference? ...
  • So you think that the human eye will always perceive a resolution difference when stopping down to any aperture, using any resolution of sensor to capture the image? No-one disputes that the ...
  • If you really want a formula, then here we go. Bob, you should red this too. We're going to consider two camera systems with sensors with resolution b and s when b > s. We're also going to consider ...
  • As I've repeatedly said, including in the post you quoted, indeed the very line you quoted, I'm referring to the peak visible resolution, not the peak resolution. There's an important difference. T ...
  • He didn't even look at pixel size. There is zero investigation there of whether or not pixel size makes a difference. given that the photo.net page that lays out the calculations refers to film ...
  • And where exactly does it prove me wrong? It would be helpful if you elucidated rather than making bald assertions.
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Last upload Dec 4, 2012