Adey Baker
Member
Won't physics also become the limiting factor in the form of diffraction? (where the wave patterns of light are disrupted when they encounter a solid surface, such as film/sensor/aperture blades, etc.)
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EOS 50D, it's officially announced (1 Viewer)
- Thread starter nigelblake
- Start date
Won't physics also become the limiting factor in the form of diffraction? (where the wave patterns of light are disrupted when they encounter a solid surface, such as film/sensor/aperture blades, etc.)
Jim Lundberg
Well-known member
Nigel,
Thank you, and if I follow your math, the 50D is about 37% wider and higher than the Rebel XT at 3456x2304. This is something like adding a 1.4x teleconverter without the aperature reduction forced by the teleconverter. And, maybe, if the hype about reduced noise at the higher ISO is correct, the 50D would be a better purchase for my brother than upgrading lenses.
Regards, Jim
Yup. Stop down to F11 or even F16 and you have no advantage over a ~12MP sensor. And then most lenses are far from diffraction limited when wide open, and only really peak at about F8. So most lenses will not be using the full 15MP. And that assumes the best technique on a solid tripod (or fast shutter speed) at low ISO.
It is curious that when the D200 and then the D300 appeared, there was some quite aggressive poo-pooing from many Canon users who said that 8MP was more than enough.
Still, it looks to be a very nice camera, subject to confirmation in use. Now all we need is for Nikon to provide a 40D like camera at a similar price point, then I'm happy.
Adey Baker
Member
D90? Looks to be the nearest and if Canon keep the 40D in production at the current price then Nikon will have to bring the price of the D90 somewhere close to it.
tjsimonsen
Well-known member
Certainly, but I was referring to the naked sensor. But off course you are right: if the sensor out resolves the lens, then there is not point in increasing the pixel count.
Thomas
tjsimonsen
Well-known member
Realistically speaking it is enough more than 90% of the time. It allows you to print out in 12'*8' at 300dpi, (well almost, technically you need 8.3mp to do that) and corresponds roughly to what you can get out of a 100ISO 35mm slide with a good scanner in my experience.
One thing is what we need. What we want is another matter altogether B
Thomas
nigelblake
don't re member
But many Canon users were used to the 16.7 Mp 1Ds MkII (Nov 2004) which had been available for a year when the the D200 (Nov 2005) was realeased.
Interesting if dated reading on diffraction here
Yes but that is so-called full frame which can handle 20+ MP so they are different beasts.
Yes a 6MP camera can produces superb A4 prints which look rasor sharp given decent technique. I agree with the scanner comment.
The problem with the D90 is that it is a consumer grade camera, with plastic body, and no MLU. So it is useless for my purposes. Whereas my understanding is that the 40D is a pro-grade camera, though not as well sealed and robust as the 1Ds series of course. Obviously each system has its own strengths, but I happen to prefer Canon's approach to APS bodies.
Markulous
Well-known member
Reading from the D90 spec:
Materials - The body is made of a combination of aluminum alloy and plastic.
Durability - Shutter units are durable up to approx. 100,000 cycles
So, sounds remarkably like the 50D! But I'm sure that being a 'semi-pro' must make some difference (tho' it sounds remarkably like marketing-speak - I look at the spec myself!)
Having said that, I can't take the D90 seriously with it's video recording capability (but apparently we can expect this with Canon, they just lag behind!)
Personally, as far as the 50D goes, I have no interest in more pixels (I avoid cropping into my pics) but I would be interested in higher ISOs if the noise is controllable (like on D300) - alas we're still stuck with inferior +/- 2.0 exposure compensation (unlike Nikon's +/- 5.0)
Materials - The body is made of a combination of aluminum alloy and plastic.
Durability - Shutter units are durable up to approx. 100,000 cycles
So, sounds remarkably like the 50D! But I'm sure that being a 'semi-pro' must make some difference (tho' it sounds remarkably like marketing-speak - I look at the spec myself!
)Having said that, I can't take the D90 seriously with it's video recording capability (but apparently we can expect this with Canon, they just lag behind!)
Personally, as far as the 50D goes, I have no interest in more pixels (I avoid cropping into my pics) but I would be interested in higher ISOs if the noise is controllable (like on D300) - alas we're still stuck with inferior +/- 2.0 exposure compensation (unlike Nikon's +/- 5.0)
Reading from the D90 spec:
Materials - The body is made of a combination of aluminum alloy and plastic.
Durability - Shutter units are durable up to approx. 100,000 cycles
So, sounds remarkably like the 50D! But I'm sure that being a 'semi-pro' must make some difference (tho' it sounds remarkably like marketing-speak - I look at the spec myself!
Having not examined a D90, I am having to make assumptions. But having examined a D70 and a D80, I would expect the D90 to have a metal frame (basically a plate to which components are bolted, and maybe a metal base plate too) held within a plastic shell. The problem with that is that it does not offer the rigidity of a metal shell. If you have ever mounted a large lens on a D70, which itself is on a tripod, you would have been alarmed at the degree of warping of the camera base. I know the D80 to be a lovely camera, but in some respects it is no D200. And I suspect the D90 will be a lovely camera, but no D300. I suspect the 40D and 50D are a significant step up from the D90 in some respects e.g. build and MLU. Now if you have done lots of macro work with a long-ish lens, you will know the value of MLU. Basically there are many shots that cannot be achieved without it. In my case that amounts to most shots. So for me the D80/D90 is not really usable. The D200/D300/40D/50D are usable. That is not marketng speak. Of course the D90 is not targeted at me, and for its target market it is superb. In fact I am sure a D90 coud be used by many pros for many purposes. Pro and consumer grade are somewhat vague terms.
Markulous
Well-known member
Have used MLU occasionally on my SD10 but found little difference (I gather it should be used in the 1/10-1/50 region for max benefit) and never in my many macros (as I'm usually handheld above this figure or tripoded below! |=)|) but I only use a 105mm and 150mm, nothing greater than 1:1
Hirundapus
Well-known member
Sure, but if your bird is tiny in the sensor of your frame and you want to print the Bird at A4, many more than 6MP in your sensor will be very useful, but at what point does the pixel count reach its theoretical maximum for this? An uninformed guess suggests 15mp (x the 1.6 crop factor) may be about it?
stevetb
Registered user
Just out of interest, and no offence intended, but when would you use that much exposure compensation? Surely if you were in desperate need you could change the exposure manually?
Markulous
Well-known member
No offence taken in the slightest! |=)|
Sunrise/sets I used to regularly go down to -3.0 to prevent burned highlights (on my 3 year old Sigma SD10!). With the rapidly changing light I can very easily use Exp Comp to adjust the exposure whereas I have to estimate if I shift to manual and you can't easily verify the change in light levels (camera just informs you you're beyond -2.0). The 1D gives you +/- 3.0 and Nikon appears to give +/- 5.0 across their dSLRs.
I guess the answer is manual and an external light meter but that just seems so unecessary! Or, I guess an ND Grad to control the sun
One theory I have for the reduced Exp Comp is that Canon are aware that the cameras are not too good at recording detail in the shadows - the dynamic range seems less than my SD10 (I use a 350D)
Markulous
Well-known member
Flippin' heck I'm after sunrises not closeups of the sun! LOL! :-O
But you're right of course. It's just a pain to monitor. 30 secs later the light will've changed so got to start again - and if I'm moving location too........ :-C
This is as informed a discussion as I have seen online:
http://www.luminous-landscape.com/tutorials/resolution.shtml
So to use 15MP you generally need to stop the lens down to about F8, use a low ISO, and perfect technique. And many if not most lenses have CA that renders the image less than appealing if blown up too much.
Hirundapus
Well-known member
Many thanks Leif. A really interesting link, even if most of it is over my head. The bottom line seems to be that the 15mp 50D will be more than any confirmed cropper like me will ever be able to get out of any sensor, so I will never have to lust over more pixels in the 60D! To buy a 60D, it will have to offer something different that I really want - like autofocussing my f4 lenses with a 2x converter!
