as i said, you are showing MTFs. multiplying MTFs is not the same as multiplying resolutions. multiplying MTFs is convolving resolutions. your link even says that and has a first order approximation formula highlighted in a big green box entitled "Resolution of an Imaging System (Old Formula)". that is the formula i used when i got my D3X to figure out where i should be aiming for target resolving power for my lenses because i could do it on a calculator. actually multiplying MTFs is messy because you either assume a mathematical form for the sensor and lens MTF or you do it numerically by digitizing the MTF chart and taking its dFFT. both take a lot of time unless you have a program set up for it like Matlab. once you have that then inverting the dFFT gives you the system resolution curve.
Herb...
afm901 wrote:
"The beauty of working in frequency domain is that the response of the entire system (or group of components) can be calculated by multiplying the [MTF] responses of each component."
I never said we were multiplying resolutions. The MTF of a higher resolution sensor is higher than that of a lower resolution sensor. I never said it was linear, either.
The point is, a higher resolution sensor is always going to offer more resolution in the final image than a lower resolution sensor...even if the lower resolution sensor out resolves the lens.
and i said have you done the numbers? is 1-2 lp/mm difference something you are going to see because that's the order of the difference unless the sensor and lens are pretty closely matched.
Herb...
afm901 wrote:
I never said we were multiplying resolutions. The MTF of a higher resolution sensor is higher than that of a lower resolution sensor. I never said it was linear, either.
The point is, a higher resolution sensor is always going to offer more resolution in the final image than a lower resolution sensor...even if the lower resolution sensor out resolves the lens.
Cormac wrote:
The optical formula is unique. Your copy can't be that much better than anyone else's. It's just not possible.
Oh yes it can. The 50mm f/1,4---and the fast 50's in general--- have traditionally(going back to the 1970's in my experience) been THE most variable in quality of assembly of all Nikon lenses.
My current Nikon 50/1.8 Ai, for example, is pathetic compared to the first Nikon 50/1.8 Ai I had back in the early 1980's.
HerbChong wrote:
and i said have you done the numbers? is 1-2 lp/mm difference something you are going to see because that's the order of the difference unless the sensor and lens are pretty closely matched.
I don't have to do the numbers. I am not trying to quantify how much much better an image will be. I am saying that the the higher resolution the sensor, the better the image will be regardless of what lens you use. That's all.
What we need to see is a test where someone shoots a test target to see how many lp/mm the D700 and D800 will resolve with various lenses. That will prove most illuminating.
afm901 wrote:
I don't have to do the numbers. I am not trying to quantify how much much better an image will be. I am saying that the the higher resolution the sensor, the better the image will be regardless of what lens you use. That's all.
What we need to see is a test where someone shoots a test target to see how many lp/mm the D700 and D800 will resolve with various lenses. That will prove most illuminating.
Scott
people, you worry too much about technology.
Can D800 with 35G wide open resolve face with the same amount of details like when captured from same position with 85G? Hellyea. So, frequency here, lps there, test targets elsewhere, i am enjoying my megapixels.
worst case scenario? SOOC Jpeg Small (size priority, max compression), full resolution. Jpeg is only about 2MB big. 35G wide open, the lens which is in every test said to be "unsharp". So this is as bad as it gets:
you can be sure that raw will look better, but for now i am too lazy to do some comparison, but you can take this further compressed and 6x downsized photo to photoshop, apply unsharp mask 100% at 0,9px and see how little girl's eyes will look printed on canvas 73in x 50in.
those are known well enough to put numbers down within a few percent depending on what assumptions you make on Bayer demosaicing and AA filter strength just from knowing the sensor well spacing. lens designer's calculated MTF graphs are also known from manufacture's specifications.
i did a quick spreadsheet on system resolution as a function of lens and sensor resolution as per the approximate system resolution formula right next to the Norm Koren page you referenced for some realistic lens and DSLR camera resolution values. this forum will ruin the formatting but copying back into a spreadsheet lets you see the results more neatly aligned.
i picked numbers that correspond to realistic camera resolution across the top and lens resolution down the left. it doesn't matter if you use lp/mm or l/mm so long as you use the same for both camera and lens under the same contrast assumptions. they're both measuring the same thing using different units. these numbers here assume lp/mm if you want them to be reasonably close to typical DSLRs.
it's not the output numbers that matter so much as the change in output as you move down and right. the biggest changes occur when lens and sensor resolutions are closest and drop off sharply as they become too different. in and around 50lp/mm, i doubt most people could see the difference between 45lp/mm and 50lp/mm and that's why the numbers matter.
Herb...
afm901 wrote:
What we need to see is a test where someone shoots a test target to see how many lp/mm the D700 and D800 will resolve with various lenses. That will prove most illuminating.
I think this is the point, it isn't just Canon fanboy's running their mouths about the camera, it seriously lacks the IQ that Nikon is known for. At least from what I've found. Your example is perfect, grainy and lacking any real crispness... My old D3s outshines the D800 in ALL categories with the exception of MP count.
My D800 shows grain at almost ALL ISO's and the AF is only slightly better than the D700. I've tried to love this camera but shooting my af tuned lenses at f8 on subjects of more than 10' always give the same issue. They all seem to lack any real contrast, the details seem smeared and there is grain all over the place. Same result if I shoot wide open. Oh and the more out of sharp focus an image is, the more grain is present.
Thank GOD that I'm moving to video cause that is where the D800 shines, otherwise, I'd give this thing away.
I think this is the point, it isn't just Canon fanboy's running their mouths about the camera, it seriously lacks the IQ that Nikon is known for. At least from what I've found. Your example is perfect, grainy and lacking any real crispness... My old D3s outshines the D800 in ALL categories with the exception of MP count.
My D800 shows grain at almost ALL ISO's and the AF is only slightly better than the D700. I've tried to love this camera but shooting my af tuned lenses at f8 on subjects of more than 10' always give the same issue. They all seem to lack any real contrast, the details seem smeared and there is grain all over the place. Same result if I shoot wide open. Oh and the more out of sharp focus an image is, the more grain is present.
Thank GOD that I'm moving to video cause that is where the D800 shines, otherwise, I'd give this thing away....Show more →
Just wondering if you read the post? It was shot @ F1.4 on a 35mm lens. Hard to expect much more sharpness/contrast on a 35mm lens wide open. I don't know what kind of lenses you are using though, but with my 14-24mm, 35mm and 70-200mm I am able to get tack sharp pixels on this monster. The lack of contrast imo, is due to the very large dynamic range and can easily be fixed in post processing by setting the white and black points.
My shots just don't agree with yours as lacking contrast, smeared details and huge amounts of grain.
I sold my 35 months ago but from what I recall with my 35 wide open, the results were like any other. DR, I don't see it...I can't pull back anything anymore than I did on my previous bodies.
My 14 2.8D, 24-70 2.8G, 50 1.4G, 50 1.8G, 85 1.8G and 70-200 2.8G VR all render the same. At close focus, less than lets say 10 feet, I get AMAZING results with my lenses fine tuned around -15. Once my subjects crosses that invisible line of distance, the camera changes...it's hard to explain. I was saying that I can shoot wide open or at f8 and get the same results; close focus - sharp, any distance - suckfest!
Sounds like some issue with your phase detect AF. Have you tried live view focusing? Also, there really is no more highlight headroom for dynamic range. It is the shadow detail that is amazing and I will underexpose to save the highlight detail and then push the shadows in post.
I think the problem here is that Nikon isn't doing a good enough job with their QC on this body. I think they were so eager to get this camera out there to compete with the 5D Mark II (video/mp) and the Mark III, that they were just doing what ever they could to get them out. I've seen some people posting images that BLOW MY MIND but the above image and what I've received from both of my D800's isn't anything I'd call mind blowing.
