All right ime back
a high percentage of photography is done on DX sensors with FX lenses,bloody hell j-see we are in agreement again 
Nikon's New 300mm f/4 Looks Impressive
- Thread starter Rob Bye
- Start date
All right ime back
a high percentage of photography is done on DX sensors with FX lenses,bloody hell j-see we are in agreement again Bengt Nyman
Senior Member
Nothing happens. You simply get pictures with different resolution, and usually with different ISO capabilities due to differences in pixel size as well as due to differences in effective sensor area versus inactive or conductor-shaded sensor area.
Ok so I didn't read every comment on this lens so far (bad me.... TLDR) lol.
Anyhow, I'm curious how this thing would handle being smacked on to a TC-20E? Could this end up being the least expensive 600mm prime setup on the market with better IQ than the Sig/Tam 150-600?
Hmmmmmmmmmmmmmmmm......
Anyhow, I'm curious how this thing would handle being smacked on to a TC-20E? Could this end up being the least expensive 600mm prime setup on the market with better IQ than the Sig/Tam 150-600?
Hmmmmmmmmmmmmmmmm......
Bengt Nyman
Senior Member
LOL. You guys are funny. You even agree to misunderstand each other and celebrate it with a big handshake.All right ime back
It can be done at a loss of IQ on static subjects,i have seen some results but it was not a way i would have gone,too many limitations.
If you simply get photos with a different resolution; what is the difference between putting an FX lens on a DX vs FX?
A lens does not enlarge anything on a DX; it simply is a smaller surface area with a specific resolution.
Bengt Nyman
Senior Member
J-see, do you ever read, or do you just talk ?
Considering the fact you wrote the most uninformed reply I read, I prefer to talk.
Let me remind you:
Crop factor implies "size relative to a FF sensor". That's all. Whether I put an FX 300mm on a micro or a Micro 300mm; I get the exact same image. How big that image is (on my screen) depends on the resolution of my sensor. In terms of light, the same lens on whichever sensor makes no difference since the sensor is "receiving" those photons.
The whole crop factor thing is more confusing than it needs to be and most got it wrong in the beginning; myself included.
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Bengt Nyman
Senior Member
J-no-see, master of confusion.
I am not touching that one.
I am not touching that one.
There's a lot confusing about the crop factor since they also throw in equivalent field of view or even equivalent focal length, and many have the impression the crop factor is responsible for enlarging the shot while that has all to do with the resolution of the sensor. Then there's the "using the best part of the lens" myth.
Any equivalency is only equivalent in retrospect to the size of a full frame sensor, but in reality, no enlarging or increase in focal length actually takes place. It would only appear that way because the sensor size only captures a fraction of the same area of a full frame sensor. If only APS-C sized sensors existed, there wouldn't even be the term "crop factor" unless then talking about sensor even smaller than APS-C.
Spottydumplings
Senior Member
J-no-see, master of confusion.
I am not touching that one.
Not sure if you are deliberately trying to be inflammatory but that is the way that it's coming across:upset:.
I have to say that I agree with @mikew and [MENTION=31330]J-see[/MENTION] on this one and would go further to suggest that using a lens designed for a larger sensor is BETTER; as you are only using the "sweet spot" towards the centre (sorry proper English), therefore, avoiding any dodginess at the edges.
Enlargement indeed only occurs on our computer screens since pixels are translated into digital dimensions and when we put the one shot next to the other, the one looks larger. In that sense my D810 takes "larger" shots than my D750 simply because it has more megapixels but the image that is cast on the sensor and the size of the sensor are identical.
Spottydumplings
Senior Member
Sorry if I am perpetuating the myth... I was certainly under that impression
I dont think its a myth its more a leftover from the time lenses struggled to perform well at the corners,there will still be some FX lenses like i think the 24-85 which has a tendency to drop IQ on the corners,if its used on a smaller sensor and the image circle is cropped then the less good areas dont get used.
Sorry if I am perpetuating the myth... I was certainly under that impression
It depends on how you apply the "myth".
Ignoring the quality differences between sensors; an FX lens delivers the exact same quality to the sensor whether it is an FX or DX sensor. The weaker part of the lens gets lost on those smaller sensors but the best part isn't any better; it's the exact same. That an FX lens delivers a better image than a DX lens on a DX sensor is only under the assumption the DX lens we compare it to has an equal quality at the center and a lower quality further from there. There are plenty of old FX lenses of which even the best part can't compete with a good DX lens.
Bengt Nyman
Senior Member
Yes, if you ignore, size, weight and price.
Bengt Nyman
Senior Member
Excellent question.
According to existing tests we know the following:
Tamron @600: DxO 12 PMP, LenScore resolving power 729, LensTip image resolution 36LP/mm
Sigma S @600: DxO -------, LenScore resolving power 884, LensTip image resolution 38LP/mm
Nikon 300@300: DxO ------, LenScore resolving power 924, LensTip image resolution 42LP/mm
Assuming that the TC20 reduces the resolution by a rumored 27% we get:
Tamron @600: DxO 12 of 36PMP, LenScore 729, LensTip 36LP/mm
Sigma S @600: DxO -------------, LenScore 884, LensTip 38LP/mm
Nikon 300@600: DxO ------------, LenScore 677, LensTip 31LP/mm
This alone suggests that the new Nikon 300 with a TC 20 can not compete with either Tamron, Sigma C or Sigma S.
I see no optical disadvantages in using a lens with an image circle much larger than the sensor. Here are some facts
. Unless the lens is designed for copy work and is absolutely linear, is is sharper in the centre and vignettes less. Check the MTF curves for most lenses.
. The so called magnification factor of a smaller with respect to a FF sensor, is there because the smaller sensors have higher pixel density. If a CX, DX and FX sensors are all 24MP, then there will be more pixels per square mm of the sensor in a CX than a DX sensor. Similarly a DX sensor will have more pixels than a FX sensor. To get the pixel density of a 24MP DX sensor, an FX sensor needs to be around 56MP.
. If all the sensors had the same pixel density and you took images with CX, DX and FX sensors, then when you superimpose the images of CX on DX and DX on FX, you will find no difference, just that the CX image will be smaller than DX which it self will be smaller than FX.
. The major disadvantage of using a lens with a larger image circle (that is lens designed for a bigger sensor) is the size, and the resultant cost. There for a Native lens design for the Nikon J series will be appreciably smaller (and may be cheaper) than that designed for FX sensor. We can see that happening in DX world. The 35mm F1.8DX lens is smaller and much cheape than its FX version.
Another example of lenses designed for larger image circle are Meduim Format lenses. These were designed for 60mm square negative, they are massive. Just compare the 80mm F2.8 (standard MF lens) with 85mm F1.4, both the size, weight and the cost are more than double for MF compared to FF.
. Unless the lens is designed for copy work and is absolutely linear, is is sharper in the centre and vignettes less. Check the MTF curves for most lenses.
. The so called magnification factor of a smaller with respect to a FF sensor, is there because the smaller sensors have higher pixel density. If a CX, DX and FX sensors are all 24MP, then there will be more pixels per square mm of the sensor in a CX than a DX sensor. Similarly a DX sensor will have more pixels than a FX sensor. To get the pixel density of a 24MP DX sensor, an FX sensor needs to be around 56MP.
. If all the sensors had the same pixel density and you took images with CX, DX and FX sensors, then when you superimpose the images of CX on DX and DX on FX, you will find no difference, just that the CX image will be smaller than DX which it self will be smaller than FX.
. The major disadvantage of using a lens with a larger image circle (that is lens designed for a bigger sensor) is the size, and the resultant cost. There for a Native lens design for the Nikon J series will be appreciably smaller (and may be cheaper) than that designed for FX sensor. We can see that happening in DX world. The 35mm F1.8DX lens is smaller and much cheape than its FX version.
Another example of lenses designed for larger image circle are Meduim Format lenses. These were designed for 60mm square negative, they are massive. Just compare the 80mm F2.8 (standard MF lens) with 85mm F1.4, both the size, weight and the cost are more than double for MF compared to FF.