Sigma lens design trickery?
Dec 8, 2015 17:24:27 #
Let me preface this by saying I have looked at a number of reviews lately and can't specifically remember the source of this particular review or for which lens it was about. However, I know that some hogger will probably demand a source so I'll try to find the review again.
I was recently reading a review of one of Sigma's recent lenses and came across an interesting comment made by the reviewer.
As many here know Sigma has recently released a number of new lenses (Art) that have exhibited extraordinary sharpness, not just at the center but also extremely good corner and edge sharpness. Apparently this is not just due to superior optical design...although Sigma seems to be getting pretty good at that.
In the review I read the author claimed that what Sigma is doing with these lenses is having them project an image circle that is larger than needed to fully cover the sensor. As a result the sensor effectively crops out the far edges and corners where you could expect image sharpness to fall off.
He also said that this is not being done by Sigma alone...that other lens makers are using the same trick. I remember he specifically mentioned Nikon and perhaps Canon.
I was recently reading a review of one of Sigma's recent lenses and came across an interesting comment made by the reviewer.
As many here know Sigma has recently released a number of new lenses (Art) that have exhibited extraordinary sharpness, not just at the center but also extremely good corner and edge sharpness. Apparently this is not just due to superior optical design...although Sigma seems to be getting pretty good at that.
In the review I read the author claimed that what Sigma is doing with these lenses is having them project an image circle that is larger than needed to fully cover the sensor. As a result the sensor effectively crops out the far edges and corners where you could expect image sharpness to fall off.
He also said that this is not being done by Sigma alone...that other lens makers are using the same trick. I remember he specifically mentioned Nikon and perhaps Canon.
Dec 8, 2015 17:35:50 #
That is exactly what a FF lens on an APS-C body does.
Old trick, works well, all you get is the sweet spot.
Old trick, works well, all you get is the sweet spot.
Dec 8, 2015 17:44:41 #
robertjerl wrote:
That is exactly what a FF lens on an APS-C body does.
Old trick, works well, all you get is the sweet spot.
Old trick, works well, all you get is the sweet spot.
I fully understand that however there is a difference here as this is purposely being done on lenses designed for full frame bodies.
Dec 8, 2015 17:45:42 #
Dec 8, 2015 17:49:25 #
Not sure that I understand why you perceive this to be a problem-if this is done to make images better, who cares.
Dec 8, 2015 17:52:47 #
flip1948 wrote:
I fully understand that however there is a difference here as this is purposely being done on lenses designed for full frame bodies.
So! Makes sense to do it that way. And cheaper than trying make a "just right" image circle that is that sharp.
All lenses project a bigger circle than the sensor size, other wise you would have the corners of the frame cut off.
Only draw back, the lens will be a bit bigger and heavier.
Dec 8, 2015 17:53:11 #
travisdeland wrote:
Not sure that I understand why you perceive this to be a problem-if this is done to make images better, who cares.
Never said I had a problem with it....just interesting.
Dec 8, 2015 19:34:51 #
flip1948 wrote:
Never said I had a problem with it....just interesting.
I agree. Interesting solution...
Dec 8, 2015 21:03:59 #
flip1948 wrote:
I fully understand that however there is a difference here as this is purposely being done on lenses designed for full frame bodies.
They're positioning themselves for future cameras with XLF sensors (Extra Large Frame)
Always fun to start a new rumor......
Dec 9, 2015 06:40:50 #
flip1948 wrote:
Never said I had a problem with it....just interesting.
Are you sure? Is your other hobby watching paint dry?
Dec 9, 2015 07:42:42 #
flip1948 wrote:
There's no "trick" involved; this is normal practice and something which has always been a feature of many lenses particularly those of "higher quality". In a cheaper lens, manufacturers can afford to trim the diameter of lens elements because border performance is unlikely to be criticised by the User. ... In the review I read the author claimed that what Sigma is doing with these lenses is having them project an image circle that is larger than needed to fully cover the sensor. As a result the sensor effectively crops out the far edges and corners where you could expect image sharpness to fall off.
He also said that this is not being done by Sigma alone...that other lens makers are using the same trick. I remember he specifically mentioned Nikon and perhaps Canon.
He also said that this is not being done by Sigma alone...that other lens makers are using the same trick. I remember he specifically mentioned Nikon and perhaps Canon.
Dec 9, 2015 08:09:46 #
Pablo8
Loc: Nottingham UK.
This has been done for years. All of my lenses for the 5 x 4 Sinar cover a bigger circle than the 5 x 4 area. That is how movements IE...swing / tilt / rising front / cross front..etc. will work. Simpuls!!
Dec 9, 2015 08:35:31 #
Dec 9, 2015 09:40:29 #
flip1948 wrote:
I fully understand that however there is a difference here as this is purposely being done on lenses designed for full frame bodies.
yes, and tires are a trick to make your car ride smoother, and they're all doing it
Dec 9, 2015 10:16:12 #
DirtFarmer wrote:
They're positioning themselves for future cameras with XLF sensors (Extra Large Frame)
Always fun to start a new rumor......
Always fun to start a new rumor......
I think those will be designated as FFXL and there will be, of course, the FF2XL. :lol:
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