jorkata wrote:
The 7D has fewer megapixels than the 5DII (18 vs 21).
Comparisons are showing that it's softer than the 5DII at the pixel level - when these comparisons are supposed to favor the 7D.
So, why is the 7D still softer? Not talking about noise here.
If it really is softer, and I think the jury's still out on that, then these will be the reasons. Don't forget that for the same pixel sharpness the 7D NEEDS SHARPER LENSES THAN THE 5D2 since its photosites are much smaller and its absolute resolution is higher. Also it has more noise at any given iso and noise affects detail.
I think we are going to see that with the right lens and aperture at low isos the 7D can come very close to the 5D2's maximum resolution. But there are many circumstances in which the 7D will get less sharpness PER PIXEL and over the image because of the factors that affect absolute resolution as described above.
In other words it will always be easier to get great sharpness with a 5D2 because it is full frame. But under the right circumstances with skilled and careful use the 7D can probably get very close. I don't believe that reviewers and photographers are bearing those considerations in mind when examining the 7D's detail limits.
The pixelologists are in this thread
Pictures are posted in Nature and Wildlife, and other forums. I posted some nice 7D bird pictures there. Mazing did not ruin those photos.
I dont think the pixel police know the "Nature Forum" even exists they need to look at Conrad Tan's 7D pics and try to tell us they arnt sharp
brainiac wrote:
Don't forget that for the same pixel sharpness the 7D NEEDS SHARPER LENSES THAN THE 5D2 since its photosites are much smaller and its absolute resolution is higher.
FF is 2.56x larger than 1.6x.
You are claiming that the 7D NEEDS SHARPER LENSES THAN THE 5D2.
But as I said already, the new G11 has a 9x smaller sensor than the 40D - and yet, they are equally sharp.
So, lens sharpness does not seem to be a good explanation why the 7D is softer than the 5DII.
I'd say it's the sensor.
jorkata wrote:
FF is 2.56x larger than 1.6x.
You are claiming that the 7D NEEDS SHARPER LENSES THAN THE 5D2.
But as I said already, the new G11 has a 9x smaller sensor than the 40D - and yet, they are equally sharp.
So, lens sharpness does not seem to be a good explanation why the 7D is softer than the 5DII.
I'd say it's the sensor.
If you tested absolute resolution of the G11 lens against all of the Canon L's, the G11 lens would probably beat them all by quite a margin. P&S lenses are jewels compared to 135 format lenses. They have to be much sharper in absolute terms, and they are.
The 7D on the other hand can use full frame lenses such as those which fit the 5D2. It is the highest absolute resolution EOS camera ever made and as a result the 7D's per pixel sharpness tests EOS lenses harder than any previous body.
If you put L lenses on a G11 or G10 the results would be surprisingly bad.
Don't forget that the smaller a lens, the closer it approximates the perfect lens, which is just a tiny tiny hole. The larger a lens, the harder it is to maintain absolute sharpness. Really big lenses suffer from physical problems like gravity/orientation affecting shape due to the elasticity of the glass. There are many reasons why small lenses can deliver superb absolute sharpness.
jorkata wrote:
FF is 2.56x larger than 1.6x.
You are claiming that the 7D NEEDS SHARPER LENSES THAN THE 5D2.
So, lens sharpness does not seem to be a good explanation why the 7D is softer than the 5DII.
I'd say it's the sensor.
...and BTW, it's simply a scientific fact that the 7D needs sharper lenses than the 5D2 to get good per pixel sharpness. The interval of the 7D sensor is 4.3µ whereas the interval of the 5D2 sensor is 6.4µ. I hope you can understand that it takes a sharper lens to saturate detail in 4.3µ pixels than 6.4µ pixels. In fact the margin is quite big: a lens which just satisfies the 5D2 would have to get about half as sharp again in linear terms in order to satisfy the 7D. That's a lot of extra sharpness, and in any fair lens test we would regard the lens adequate for the 7D as absolutely destroying the lens adequate for the 5D2.
Of course, that's one of the major advantages of full frame: good performance from lesser lenses.
digitalbug30d wrote:
I dont think the pixel police know the "Nature Forum" even exists they need to look at Conrad Tan's 7D pics and try to tell us they arnt sharp
To be fair, Conrad's great pictures could have been taken on a 6 Mpixel camera and downrezzed to web sizes. I haven't seen him posting too many 100% or 67% crops. The issue being discussed here is whether 18 Mpixels is a sensible upgrade to 10, 12 or 15 Mpixels. Web sized images won't show that difference in detail. Only properly magnified crops and large prints can show whether the 7D captures more detail.
jorkata wrote:
The 7D has fewer megapixels than the 5DII (18 vs 21).
Comparisons are showing that it's softer than the 5DII at the pixel level - when these comparisons are supposed to favor the 7D.
So, why is the 7D still softer? Not talking about noise here.
first of all, 7D's 18 mps is roughly equivalent to 46 mps in FF with the same pixel density, and it is only fair to compare sharpness with different cameras under same sensor size
so if you have a lens which is capable of delivering 30 mps FF resolution, you should see that the 7D image taken by this lens is softer than 5D2 at pixel level. (this lens is capable to deliver all the resolution that 5D2 requires, but not the 7D requires)
if you have a lens which is capable of delivering 60 mps FF resolution, you will see that the 7D image taken by this lens should be as sharp as the 5D2 (this lens out resolves the resolution of both cameras)
of course these are based on the assumption that all other factors are the same (which may not be true) across these two bodies, like AA filter, settings, technique, etc...
EDIT: i just wanted to add that higher pixel counts will always help to bring more details to the picture at image level as long as the lens is capable of doing it, even if you actually see the higher pixel camera softer at pixel level (which means the lens is not capable of out resolving the sensor)...
Changing the subject ever so slightly to printing.
Can we assume that, without up-rezzing, that the 7D should be able to make nice A3-size prints at 300dpi? That would seem to be the theoretical limit at that target resolution?
System MTF = lens MTF, camera form-factor (FF, crop), aperture, shutter speed, sensor resolution, pixel pitch, sensor noise, printer resolution, printer gamut, paper resolution, viewing distance, etc...
The final copy (printing) is what really matters to many of us, so ALL of the elements of the "System" MTF are important.
Thank you Cameron, for bringing up a good subject.
I've seen lots of 7D's producing pictures that would make very good A3 prints, but I've also seen quite a few that have "maze"-effects strong enough to kill pixel-level fine detail if the detail isn't high-contrast - these cameras need to be down-sampled quite a lot to give perfectly sharp results.
This might be the entire difference between "good" 7D's and "unbalanced" 7D's. How large you can print/view the resulting pictures. I'm entirely with the "crowd" that say that having so many afflicted cameras (in percent) as this seems to be is not "ok" from a major camera maker company. I've tested 13 cameras so far - and TWO has been "good", eight has been "nah...." and three have been "OMG! that's BAD!"...
System MTF, the SUM of all the parts of the system is what counts as you say - when you try to find your maximum reproduction size. And the "maze" effect lowers this (if the rest of your system is up to the task!) by a noticeable margin. That is not acceptable, if you buy an 18MP camera you want 18 usable MP, not MP's that you have to downsample. Having to downsample to get "pixel-perfect" results is kind of "ok" in a 150$ compact, but not a 2500$ flagship APS DSLR.
Regarding sharpness I would say that a good sample of the 7D with a good lens is capable of very good detail resolution. A 5D2 will give you more fine detail, as each individual pixel is less noisy, and the end result can take more sharpening and local contrast enhancements without breaking up - but for a crop-camera the results can be very good.
Zeiss has a good primer on "system MTF" at http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_31_MTF_en/$File/CLN_MTF_Kurven_2_en.pdf
Page 22 starts to do some real testing with a 12MP FX camera vs a 24MP FX when both are tested with a 60F/2.8Macro F/22 (both systems are diffraction affected. Not LIMITED - affected!). The results are pretty clear, as they should be if you give it some actual thought.
skibum5 wrote:
too bad the 7D white paper is not out yet, not that they would necesarily get into this sort of detail about what they may or may not have done
the new 1D4 white paper seems to imply a normal 3-color RGB filter like with previous bodies
i'll try to fire off a letter to canon tech within the next couple of days and drive down there as well, if need be
Do you have an address and/or a contact person to write? If so, can you share this information with us?
Please also let us know the results of your query and/or visit. Thanks!
brainiac wrote:
The trick is don't buy on a Friday or a Tuesday. Or a Sunday.
Glad that's settled!
My trick will be to postpone my next "DSLR-for-whales-and-other-critters" purchase decision until spring, when things will have settled down with the 7D and the hopefully new camera announcements from Canon, Nikon and Sony have been made.
I kinda feel like Mulder from the X Files: I want to believe (in the 7D)!
digitalbug30d wrote:
I dont think the pixel police know the "Nature Forum" even exists they need to look at Conrad Tan's 7D pics and try to tell us they arnt sharp
funny how some of the pixel police already have many more photos on their (not even barely begun) websites than you do on yours, including, yes, far more strictly nature photos too
and how some of them have posted to the nature forum years before you even joined FM
something i saw on another thread here that has a lot of truth to it:
the best advice I ever got on FM? just go out and shoot
the worst advice I ever got on FM? just go out and shoot
i'd be surprised if it is in any way worse than a 20D, at worst you could always downsize all the way from 18MP to 8MP or apply a lot of special NR to get rid of artifacts, and that is in the worst case scenario; even if the noise was still a tiny bit worse (which one comparison on DPR though actually did imply) i'm sure the detail would be better and shadows much better and you could find some balance, even in the worst case, that most people would consider to be better than the 20D, and again that is in the worst case possible. So I don't think you need to worry about wishing you still had the 20D at all.
i'm less certain about matching the 50D at ISO100 though, can it maintain that level of sharpness with same or less noise/artifacting?
akclimber wrote:
My trick will be to postpone my next "DSLR-for-whales-and-other-critters" purchase decision until spring, when things will have settled down with the 7D and the hopefully new camera announcements from Canon, Nikon and Sony have been made.
I kinda feel like Mulder from the X Files: I want to believe (in the 7D)!
Hi AkCclaimer, I think you need a larger sensor for your purpose and most likely with a high pixel density. Those animals are huge and the type of weather you're in demants it, I think ..
Best regards,
Bas
P.s. I'm in for a 5D2, beside my 1D3 next time we go up north Huge price drop in the Netherlands at this moment. It went down 200 dollars in a week. Something new coming this way?
Bas Breetveld wrote:
Hi AkCclaimer, I think you need a larger sensor for your purpose and most likely with a high pixel density. Those animals are huge and the type of weather you're in demants it, I think ..
Best regards,
Bas
P.s. I'm in for a 5D2, beside my 1D3 next time we go up north Huge price drop in the Netherlands at this moment. It went down 200 dollars in a week. Something new coming this way?
HI Bas, I've been shooting whales with a 5D and 1D2n for the past 2 summers. I'd love a fast frame rate (8 or maybe even 6 fps) fullframe (with maybe 21 - 24 MPs) DSLR with decent high ISO (clean ISO800-1600). I keep waiting for the mythical 3D I am open tho to whatever becomes available in spring. If Sony offers up an "affordable" 6+ fps fullframe DSLR with good ISO 800 and video I might just try it out for whales, along with a 70-400.
The "reach" (or pixels per whale) of a crop helps with whales tho since altho they may be large (humpbacks anyway - orcas not so much), the only time you get to see most of them is when they breach (and for that, a fast frame rate really helps!). And here in the US, we're not allowed to approach closer than a 100 yards so unless they pop up next to you, you tend to be shooting from pretty far off. And yes, the weather up here can be, er, less than sunny so a realistically decent high ISO performance is important (clean ISO800 -1600 would keep me happy).
I just bought a 5D2 after deciding to wait on the 7D and 1D4 and because I really want to try video - I figured I could spend the winter learning video techniques. Fun camera. I hope you find a good price on one and put it to very good use!
cameron12x wrote:
So, you're not driving down there now? We were hoping for some inside information!
i'll see what they say, they will probably say bring it down
it is a solid 60-75 mintues to get there and if something weird happens on the turnpike, as it is wont to happen on the exit right before Canon.... i'm only on the turnpike for a a couple or so exits and yet that stretch once took 2x as long as the rest of the trip!
