Lenses and megapixels

reeftool · 04-30-2009, 07:45 AM

A good sharp prime lens will produce a very good cropped photo if you have to crop. I try to use the right length lens for the shot when i'm using a prime. If I have to crop every shot a lot then I'm using the wrong lens. The stuff that I do crop a lot is with the longer telephotos because I can't afford the lens I would like right now. In poor light where I have to shoot wide open, a cropped shot with my Takumar 200mm f4 will be much better than my Sigma 70-300 because its a much better lens. I don't think i'm wasting pixels. I do use the zooms a lot more because it's convienent.

AndrewG NY · 04-30-2009, 08:00 AM

Originally posted by Marc Sabatella

Nicely put. I suppose if you only own one prime and try to use it for shots for which is not well suited, then you'd have to crop. But the completely misses the point of using primes.

After reading your response, I realized I accidentally transposed "need" & "mean"...but I think you got my point anyway. The main time I know people start doing this is when they are shooting wildlife with their longest lens and it still isn't long enough. That's life...some of us just aren't willing to buy and/or carry SLR lenses > 300mm or so. And there may be some validity to this approach--you just might get better results cropping from a high-quality 300mm prime vs. a softer & slower 400mm zoom. But using a shorter prime like a 50 instead of a longer telephoto is essentially like "digital zoom" that most of us know is a serious quality compromise.

newarts · 04-30-2009, 08:33 AM

A person looking at a certain size displayed image can resolve only a certain number of pixels. Doesn't it follow that a sensor's pixels in excess of that number are "wasted"?

Now maybe there's a lower limit to the number of sensor pixels required to make an effective display pixel, but that doesn't change the thrust of the argument.

Iowa Dave

**jbinpg** · 04-30-2009, 02:23 PM

Sensor resolution + lens resolution = final cropping ability.

The greater each resolution is, the more you can crop without penalty. The combo of my DA* 300 and my K20D gives me enough crop ability that I can smoke many much bigger guns out there.

Jack

Jewelltrail · 04-30-2009, 11:09 PM

Quote:

ntx: Is there a flaw in my thinking? How often is cropping needed when using primes?

Proper composition eliminates the need to crop. More experienced shooters compose better and therefore need to crop less. Your thoughts apply to an inexperienced shooter, not yet skilled enough to maximize a prime's utility, but who might be able to compose better making use of the zoom's versatility.

Quote:

ntx: Also I read reviews that talks about cameras (that have 15/20 megapixels) which are good because of their cropping possibilities. Looks strange for me to pay for tenths of megapixel in order to crop them down...

It is true a 15 or 20 MP DSLR has more "cropping power" than a 5 or 10 MP camera. But remember, 15 or 20 MP is rarely needed by most people in order to print. Many people make high quality 11 X 14 prints with a 6 MP camera. So you are not wasting any mega pixels if you get the image you want and print it successfully at the size you want.

Quote:

ntx: A question arises: does a prime lens just waste sensor's mega pixels?

When used correctly, a prime will make better use of a camera's available mega pixels, because primes (most of the time) outperform their zoom counterparts in IQ. However, there are excellent zooms which outperform some lesser primes.

**jbinpg** · 05-01-2009, 09:24 AM

Originally posted by Jewelltrail

Proper composition eliminates the need to crop. More experienced shooters compose better and therefore need to crop less. Your thoughts apply to an inexperienced shooter, not yet skilled enough to maximize a prime's utility, but who might be able to compose better making use of the zoom's versatility.

It's been a while since I've read a more condescending post. There are many situations where cropping is needed. Not every photographer has his or her environment under such control that they are able to guarantee the "right" composition. Condescension reveals the narrow mind.

Jewelltrail · 05-01-2009, 09:55 AM

Quote:

jbinpg: It's been a while since I've read a more condescending post. There are many situations where cropping is needed. Not every photographer has his or her environment under such control that they are able to guarantee the "right" composition. Condescension reveals the narrow mind.

Sorry if my words appear condescending to you---my intention is only to help. May I ask you the following questions?

Did I ever say cropping is never needed?

Who composes better, experienced or inexperienced shooters?

Did I ever say any photographer has his/her environment under complete control?

Did I say I consider myself an experienced shooter? (one of the reasons I bought the K20 was, indeed, for its cropping power)

My point is a prime, usually, has more potential to maximize a camera's mega pixels, but that an experienced shooter is more apt to tap into that potential.

reeftool · 05-01-2009, 10:27 AM

I agree with the practice of proper composition but most of my cropping is because I don't have a lens long enough and can't afford to buy one right now. A lot of us enjoy getting outside and shooting pics of birds and wildlife and don't have those long, fast lenses the pros use so we get the best glass we can afford and crop if we need to.

**Rondec** · 05-01-2009, 10:44 AM

I have to respectfully disagree that primes are sharper than zooms. Unless you are a pixel peeper, a high quality zoom is indistinguishable from a prime. There are definite benefits to primes -- they are often a little cheaper, are much smaller and are faster, but at the same apertures, they are not sharper.

This is of course assuming a quality zoom - DA 16-45, DA* 50-135, etc.

res3567 · 05-01-2009, 09:19 PM

Originally posted by Rondec

I have to respectfully disagree that primes are sharper than zooms. Unless you are a pixel peeper, a high quality zoom is indistinguishable from a prime. There are definite benefits to primes -- they are often a little cheaper, are much smaller and are faster, but at the same apertures, they are not sharper.

This is of course assuming a quality zoom - DA 16-45, DA* 50-135, etc.

Have you compared a prime vs. a high quality zoom?

Show us your evedence.

Post the pics.

Venturi · 05-01-2009, 09:34 PM

With tongue in cheek I offer my "esteemed" opinion of the three situations where one needs to crop:

a) You can not get close enough to your subject with the focal length(s) you have (moving planes, trains, automobiles, etc.).
b) You should not get close enough to your subject with the focal length(s) you have (lions, tigers, bears & brides).
c) You screwed up and didn't get as close enough to your subject...

In my case it is nearly always c)

dave sz · 05-01-2009, 09:36 PM

I'm surprised no one has told the OP to hold off buying that k200 and wait for the k-7 to drop...

**Ash** · 05-01-2009, 10:50 PM

My .02 worth would be to say that there's more to lenses than resolving power.
ie. Primes, even if better resolving than zooms, generally have better colour rendition, contrast and are faster than zooms.

Nevertheless today's zooms (like the DAs) are VERY good and have almost everything that primes have in terms of IQ bar the speed. But again, bear in mind that zooms also have their weak spots that if compared with primes would pale in performance, eg. it's probably unfair to compare the DA 12-24 at 24mm to the FA* 24 or a DA*16-50 at 16mm to a DA* 15

res3567 · 05-01-2009, 10:54 PM

Originally posted by Venturi

With tongue in cheek I offer my "esteemed" opinion of the three situations where one needs to crop:

).
b) You should not get close enough to your subject with the focal length(s) you have , bears & brides).

LOL!!!!!!!!!!

Marc Sabatella · 05-01-2009, 11:38 PM

Originally posted by Venturi

With tongue in cheek I offer my "esteemed" opinion of the three situations where one needs to crop:

a) You can not get close enough to your subject with the focal length(s) you have (moving planes, trains, automobiles, etc.).
b) You should not get close enough to your subject with the focal length(s) you have (lions, tigers, bears & brides).
c) You screwed up and didn't get as close enough to your subject...

In my case it is nearly always c)

FWIW, taking this list seriously (and it *is* a good list), there is one important thing missing:

d) changing distance to subject would adversely affect the perspective

That's actually the strongest argument n favor of zooms, in my opinion. "Zooming with one's feet" changes perspective; changing focal lengths does not. Ideally, you'd first choose your position based on perspective concerns, then chosoe the focal length that provides the best composition from that perspective. If you don't have that focal length available, then that's where you'd want to shoot shorter and crop.

Still, if you have a decent assortment of primes available, you wouldn't have to crop *much* - and it's also possible that a small change in position wouldn't *entirely* ruin the perspective.

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04-30-2009, 07:45 AM	#16
reeftool Pentaxian Join Date: Dec 2007 Location: Upstate New York Photos: Gallery \| Albums Posts: 9,555	A good sharp prime lens will produce a very good cropped photo if you have to crop. I try to use the right length lens for the shot when i'm using a prime. If I have to crop every shot a lot then I'm using the wrong lens. The stuff that I do crop a lot is with the longer telephotos because I can't afford the lens I would like right now. In poor light where I have to shoot wide open, a cropped shot with my Takumar 200mm f4 will be much better than my Sigma 70-300 because its a much better lens. I don't think i'm wasting pixels. I do use the zooms a lot more because it's convienent.

04-30-2009, 08:00 AM	#17
AndrewG NY Veteran Member Join Date: Dec 2006 Location: Chappaqua, NY Photos: Gallery Posts: 688	Originally posted by Marc Sabatella Nicely put. I suppose if you only own one prime and try to use it for shots for which is not well suited, then you'd have to crop. But the completely misses the point of using primes. After reading your response, I realized I accidentally transposed "need" & "mean"...but I think you got my point anyway. The main time I know people start doing this is when they are shooting wildlife with their longest lens and it still isn't long enough. That's life...some of us just aren't willing to buy and/or carry SLR lenses > 300mm or so. And there may be some validity to this approach--you just might get better results cropping from a high-quality 300mm prime vs. a softer & slower 400mm zoom. But using a shorter prime like a 50 instead of a longer telephoto is essentially like "digital zoom" that most of us know is a serious quality compromise.

04-30-2009, 08:33 AM	#18
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	A person looking at a certain size displayed image can resolve only a certain number of pixels. Doesn't it follow that a sensor's pixels in excess of that number are "wasted"? Now maybe there's a lower limit to the number of sensor pixels required to make an effective display pixel, but that doesn't change the thrust of the argument. Iowa Dave

04-30-2009, 02:23 PM	#19
jbinpg Site Supporter Join Date: Mar 2008 Location: Prince George, BC Photos: Gallery \| Albums Posts: 3,546	Sensor resolution + lens resolution = final cropping ability. The greater each resolution is, the more you can crop without penalty. The combo of my DA* 300 and my K20D gives me enough crop ability that I can smoke many much bigger guns out there. Jack

04-30-2009, 11:09 PM	#20
Jewelltrail Veteran Member Join Date: May 2008 Location: Rhode Island Photos: Albums Posts: 4,180	Quote: ntx: Is there a flaw in my thinking? How often is cropping needed when using primes? Proper composition eliminates the need to crop. More experienced shooters compose better and therefore need to crop less. Your thoughts apply to an inexperienced shooter, not yet skilled enough to maximize a prime's utility, but who might be able to compose better making use of the zoom's versatility. Quote: ntx: Also I read reviews that talks about cameras (that have 15/20 megapixels) which are good because of their cropping possibilities. Looks strange for me to pay for tenths of megapixel in order to crop them down... It is true a 15 or 20 MP DSLR has more "cropping power" than a 5 or 10 MP camera. But remember, 15 or 20 MP is rarely needed by most people in order to print. Many people make high quality 11 X 14 prints with a 6 MP camera. So you are not wasting any mega pixels if you get the image you want and print it successfully at the size you want. Quote: ntx: A question arises: does a prime lens just waste sensor's mega pixels? When used correctly, a prime will make better use of a camera's available mega pixels, because primes (most of the time) outperform their zoom counterparts in IQ. However, there are excellent zooms which outperform some lesser primes.

05-01-2009, 09:24 AM	#21
jbinpg Site Supporter Join Date: Mar 2008 Location: Prince George, BC Photos: Gallery \| Albums Posts: 3,546	Originally posted by Jewelltrail Proper composition eliminates the need to crop. More experienced shooters compose better and therefore need to crop less. Your thoughts apply to an inexperienced shooter, not yet skilled enough to maximize a prime's utility, but who might be able to compose better making use of the zoom's versatility. It's been a while since I've read a more condescending post. There are many situations where cropping is needed. Not every photographer has his or her environment under such control that they are able to guarantee the "right" composition. Condescension reveals the narrow mind.

05-01-2009, 09:55 AM	#22
Jewelltrail Veteran Member Join Date: May 2008 Location: Rhode Island Photos: Albums Posts: 4,180	Quote: jbinpg: It's been a while since I've read a more condescending post. There are many situations where cropping is needed. Not every photographer has his or her environment under such control that they are able to guarantee the "right" composition. Condescension reveals the narrow mind. Sorry if my words appear condescending to you---my intention is only to help. May I ask you the following questions? Did I ever say cropping is never needed? Who composes better, experienced or inexperienced shooters? Did I ever say any photographer has his/her environment under complete control? Did I say I consider myself an experienced shooter? (one of the reasons I bought the K20 was, indeed, for its cropping power) My point is a prime, usually, has more potential to maximize a camera's mega pixels, but that an experienced shooter is more apt to tap into that potential.

05-01-2009, 10:27 AM	#23
reeftool Pentaxian Join Date: Dec 2007 Location: Upstate New York Photos: Gallery \| Albums Posts: 9,555	I agree with the practice of proper composition but most of my cropping is because I don't have a lens long enough and can't afford to buy one right now. A lot of us enjoy getting outside and shooting pics of birds and wildlife and don't have those long, fast lenses the pros use so we get the best glass we can afford and crop if we need to.

05-01-2009, 10:44 AM	#24
Rondec Loyal Site Supporter Join Date: Mar 2009 Location: Gladys, Virginia Photos: Gallery Posts: 27,668	I have to respectfully disagree that primes are sharper than zooms. Unless you are a pixel peeper, a high quality zoom is indistinguishable from a prime. There are definite benefits to primes -- they are often a little cheaper, are much smaller and are faster, but at the same apertures, they are not sharper. This is of course assuming a quality zoom - DA 16-45, DA* 50-135, etc.

05-01-2009, 09:19 PM	#25
res3567 Veteran Member Join Date: Sep 2008 Location: Houston Tx. Photos: Gallery Posts: 1,876	Originally posted by Rondec I have to respectfully disagree that primes are sharper than zooms. Unless you are a pixel peeper, a high quality zoom is indistinguishable from a prime. There are definite benefits to primes -- they are often a little cheaper, are much smaller and are faster, but at the same apertures, they are not sharper. This is of course assuming a quality zoom - DA 16-45, DA* 50-135, etc. Have you compared a prime vs. a high quality zoom? Show us your evedence. Post the pics.

05-01-2009, 09:34 PM	#26
Venturi Veteran Member Join Date: Mar 2008 Location: Tulsa, OK Photos: Gallery Posts: 2,636	With tongue in cheek I offer my "esteemed" opinion of the three situations where one needs to crop: a) You can not get close enough to your subject with the focal length(s) you have (moving planes, trains, automobiles, etc.). b) You should not get close enough to your subject with the focal length(s) you have (lions, tigers, bears & brides). c) You screwed up and didn't get as close enough to your subject... In my case it is nearly always c)

05-01-2009, 09:36 PM	#27
dave sz Veteran Member Join Date: Dec 2006 Location: carpentersville, IL Posts: 693	I'm surprised no one has told the OP to hold off buying that k200 and wait for the k-7 to drop...

05-01-2009, 10:50 PM	#28
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	My .02 worth would be to say that there's more to lenses than resolving power. ie. Primes, even if better resolving than zooms, generally have better colour rendition, contrast and are faster than zooms. Nevertheless today's zooms (like the DAs) are VERY good and have almost everything that primes have in terms of IQ bar the speed. But again, bear in mind that zooms also have their weak spots that if compared with primes would pale in performance, eg. it's probably unfair to compare the DA 12-24 at 24mm to the FA* 24 or a DA16-50 at 16mm to a DA 15

05-01-2009, 10:54 PM	#29
res3567 Veteran Member Join Date: Sep 2008 Location: Houston Tx. Photos: Gallery Posts: 1,876	Originally posted by Venturi With tongue in cheek I offer my "esteemed" opinion of the three situations where one needs to crop: ). b) You should not get close enough to your subject with the focal length(s) you have , bears & brides). LOL!!!!!!!!!!

05-01-2009, 11:38 PM	#30
Marc Sabatella Veteran Member Join Date: Sep 2006 Location: Denver, CO Photos: Gallery Posts: 10,685	Originally posted by Venturi With tongue in cheek I offer my "esteemed" opinion of the three situations where one needs to crop: a) You can not get close enough to your subject with the focal length(s) you have (moving planes, trains, automobiles, etc.). b) You should not get close enough to your subject with the focal length(s) you have (lions, tigers, bears & brides). c) You screwed up and didn't get as close enough to your subject... In my case it is nearly always c) FWIW, taking this list seriously (and it is a good list), there is one important thing missing: d) changing distance to subject would adversely affect the perspective That's actually the strongest argument n favor of zooms, in my opinion. "Zooming with one's feet" changes perspective; changing focal lengths does not. Ideally, you'd first choose your position based on perspective concerns, then chosoe the focal length that provides the best composition from that perspective. If you don't have that focal length available, then that's where you'd want to shoot shorter and crop. Still, if you have a decent assortment of primes available, you wouldn't have to crop much - and it's also possible that a small change in position wouldn't entirely ruin the perspective.