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Author Topic: do crop sensors really add reach?  (Read 19973 times)

jrista

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Re: do crop sensors really add reach?
« Reply #105 on: October 21, 2012, 08:20:53 PM »


LOL. Good one. :)

Humor aside, resolution is resolution. It is a rather simple spatial construct. Assuming you did not take care to address the *needs* of the 7D, sure, it is highly unlikely you'll realize the full 2.21x resolution benefit the 7D has to offer. However, that does not change the fact that the 7D DOES offer that benefit, and when you use a good lens, with solid 4-stop IS, and/or a stable tripod, the chances of realizing a close approach to that 2.21x resolution benefit are very good. If we take the moon as an example, I always set up my tripod as low as it will go, with legs out wide for maximum stability, on windless nights whenever possible, and I use a wireless shutter release with mirror lockup to actually take the photo. Assuming I photograph the moon high in the sky on dry nights when it is center of the lens, I believe I can easily realize around 2x of that 2.21x reach benefit.

If you don't think you can, or don't care to, properly utilize the tools in hand, you should probably be using different tools. It is definitely easier to get "sharp" photos with a FF sensor that has larger pixels. That just follows the line of reasoning regarding pixel size, the diffraction limit of the sensor, and the effects of camera shake.

What you just described is a better description of landscape photography than wildlife photography. Really it is, it is moonscape photography. Actually the only time I did use the 7D after I bought the 1D IV was for taking pictures of the moon.

Remember we are talking wildlife photography. If you are setting up posed pictures on posed roosts at your back yard bird feeder you can incorporate some of what you say. Probably you will not be using mirror up or a wireless release but you might. But there are other levels of wildlife photography. Wildlife photography photographs wild things, they do not always cooperate in such a clinical manner. There are times a person might be shooting off a tripod, times when they might be shooting hand held at BIF or shooting in low light situations. Now, were any of those methods "not properly utilizing the tool in hand"?  The resolution benefit decreases in real life situations, and the other benefits that the 7D offer the wildlife photographers are far greater than this one. But, how does one really quantify how much better, I just think if we base our opinions on the actual numbers we know (1.6x or 2.21x) we deceive ourselves.

I was thinking about this as well, if the 5D III AF system is as accurate as the 1D series bodies it would be a far better choice. The 7D and 5D II AF systems are not as accurate and precise as the 1D x or IV. You can have all the sensor resolution you want, if the AF system is more accurate it will give you better resolution because it is more precise in its focus.  I haven't had the opportunity to try the 5D III yet, it would be fun to compare.

Well, it depends on how you conduct your photography. As a bird and wildlife photographer myself, I use a tripod frequently. The only times when I'm not using a tripod, or a ground pod, or a bean bag in my car, is when I'm tracking something that is moving pretty quickly, like a bird in flight, or an elk chasing down a rival. I just went out yesterday, and photographed some migrating Long-Billed Dowitchers. I spent most of the time laying down in wet, silty sand, with my camera resting on my outstretched arm (and the camera battery grip resting on the ground behind my arm:



The image above is slightly softer than the one below, thanks to the fact that it was taken with a lens, the 100-400 L IS, that doesn't match the capabilities of the 7D. I did much the same thing as with the photo a number of weeks back, photographing some Sandpipers:



The photo above is quite a bit sharper, as it was taken with the 300mm f/2.8 L II IS + 2x TC III (600mm combo, far sharper than the 100-400). When I utilized the right tools the right way, the results were better. Both results are great, thanks to the fact that I wasn't just plain-old hand-holding the lens, which would have certainly reduced the resolution of both shots. I put as much stabilization behind both as I possibly could, because that's how you maximize the potential of a piece of gear like the 7D.

Now, while I completely agree that basing all of our decisions, such as purchasing, purely off of numbers is a bad idea, I disagree that the numbers are meaningless. A valid number tells you what your hardware is capable of in the best of circumstances. In the case of the 7D, it is possible to get as much as 2.2x the reach as a 5D II (or III, for that matter), r 2.6x the reach of a 1D X. In the case of Nikon cameras with high dynamic range like the D800, you can get around 13.2 stops of DR, vs. around 11 stops of DR for the 5D II, 5D III, the 7D and I would figure the 1D X. I would never base my purchasing decisions off of what DXO says, however I most definitely DO reference their "Screen" scores to learn what the hardware I already own is capable of, and where there might be room for improvement (from an IQ perspective anyway.)

All that said, obviously there is functionality well beyond the scope of the sensor that usually ends up being far more significant to one's decisions. I'd never argue that the 7D's AF system could beat a 5D III or 1D X. Neither would I claim the 7D framerate was more useful than the 1D X's frame rate, or ISO for that matter. I'd give up my 7D in a split second if someone offered me a 1D X, regardless of the 2.6x resolution/reach benefit it has over the latter.

None of that changes the fact that the 7D DOES have oodles of spatial resolution, and you can utilize most of it if you aim to.
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Re: do crop sensors really add reach?
« Reply #105 on: October 21, 2012, 08:20:53 PM »

neuroanatomist

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Re: do crop sensors really add reach?
« Reply #106 on: October 21, 2012, 09:05:50 PM »
... the 7D DOES have oodles of spatial resolution...

How many lp/mm in an oodle?   ;)
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jrista

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Re: do crop sensors really add reach?
« Reply #107 on: October 21, 2012, 09:09:39 PM »
... the 7D DOES have oodles of spatial resolution...

How many lp/mm in an oodle?   ;)

Well, I would first have to calculate exactly how many oodles the 7D has... ;)
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neuroanatomist

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Re: do crop sensors really add reach?
« Reply #108 on: October 21, 2012, 09:13:22 PM »
Touché, Sir.  :D
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PackLight

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Re: do crop sensors really add reach?
« Reply #109 on: October 21, 2012, 09:17:59 PM »
You do realize that the 300mm f/2.8L II would have looked oodles better than the 100-400mm on the full frame as well. :P

jrista

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Re: do crop sensors really add reach?
« Reply #110 on: October 21, 2012, 09:48:51 PM »
You do realize that the 300mm f/2.8L II would have looked oodles better than the 100-400mm on the full frame as well. :P

Sure, but at the same distance the 7D would still produce an image with more detail, as you would be getting a ton more pixels on subject regardless. Stabilized like I was doing it, the tiny bit of remaining camera shake might knock off that extra .26x reach factor, but a 200% improvement is still pretty incredible. I'd have needed a 1200mm f/8 lens to get the same shot at the same detail level with a 1D X. At 600mm and less than half the pixel density, a better AF system that can nail perfect focus 95% of the time is simply not going to give you enough additional detail to close the gap.

In the case of the Sandpiper, I would have used a 1D X if I had it, as I had the option to get closer. But in the case of the Dowitchers, I might have still used the 7D, since I was a bit limited in how close I could get. They were shore wading right at the border of the lake and the mud flats. The mud flats themselves were about 12 feet across, and I couldn't lay down in that stuff. It's sticky, black, gooey, sucking clay and silt mud, covered with detritus, debris, bird S___ and spitup, decaying fish, and got knows what kind of diseases. :P I'd probably have sunk a foot or more into it if I'd tried. I didn't have the option to get closer with a FF camera to make up the difference in resolution. I would have either had to use a longer lens (such as a 600mm), or use a camera with a higher pixel density, to get the kind of reach I needed.

My point is that the 7D provides a kind of value that no other camera on the market really does. It may be a noisy camera at ISO 100 and ISO 3200...but between those two, it is really a unique option that excels at what it does for those moments when you need exactly what the 7D is. ;) I'll probably always have a camera like the 7D in my kit. A high density, weather sealed DSLR with a decent AF system. Such a thing would always be my backup vs. a full frame like the 1D X or 5D III, so I could swap just in case that extra reach was really necessary. (Unless such time occurs when we have 12fps FF cameras that support 40-50mp worth of resolution and quality high ISO....in which case all bets are off!)
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natureshots

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Re: do crop sensors really add reach?
« Reply #111 on: October 22, 2012, 02:40:26 PM »
1D X vs. 7D?  No contest.  ISO 12800 on the 7D = a speckled, noisy mess.  ISO 12800 on the 1D X = a usable image.  Comes in very handy with an f/5.6 or f/8 lens or TC combo.

Well if we apply some good old DxO type summary evaluation (meaning it will have little to do with reality)

The 1D X processors are 4 times faster than the one in the 7D, and the 1D X has 2 of them. So that would be 8 x better.
But then you take the faster frame rate the 1D X is 1.5 x better than the 7D.
Then take the improved ISO, definitly 3 stops so 3 x better.
And finally take back the the 2.58 pixel density of the 7D.

So 8x1.5x3/2.58=13.95 The 1D X is 13.95 times better than the 7D.

Does it make sense? As much as if you think  you would see a full 2.21 times increase in resolution using the 7D vs the 5D II.

The 7D has dual Digic 4, not one. Your normalization is flawed and I don't believe your Scores have validity.   :P

 :-[ Oh no, it does have an error there are two processors. It would only be 7 times as good.
You forgot to adjust for inflation. I'd say 2.12452553x better.

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Re: do crop sensors really add reach?
« Reply #111 on: October 22, 2012, 02:40:26 PM »

natureshots

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Re: do crop sensors really add reach?
« Reply #112 on: October 22, 2012, 02:46:12 PM »
Also, important to point out that all of this is a pointless discussion if you are not cropping. If you can get close the bigger sensor will look better than the crop sensor pretty much 100% of the time so are you taking pictures of deer or warblers becomes the important question.

jrista

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Re: do crop sensors really add reach?
« Reply #113 on: October 22, 2012, 03:43:01 PM »
Also, important to point out that all of this is a pointless discussion if you are not cropping. If you can get close the bigger sensor will look better than the crop sensor pretty much 100% of the time so are you taking pictures of deer or warblers becomes the important question.

Thats why I keep putting in the "focal-length limited" frame of reference. If you can get closer, or use a longer lens, sure. But when you are stuck at a certain distance and can only use the same lens on a low density vs. high density camera, the high density camera is the one to use.
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PackLight

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Re: do crop sensors really add reach?
« Reply #114 on: October 22, 2012, 04:41:20 PM »
Also, important to point out that all of this is a pointless discussion if you are not cropping. If you can get close the bigger sensor will look better than the crop sensor pretty much 100% of the time so are you taking pictures of deer or warblers becomes the important question.

Very true, that is another reason I consider the crop sensor advantage isn't as big as can be implied. If you have a crop body and a full frame, and they have equal AF systems and options the Crop body would only benefit you at your longest focal length. For instance if you have the 24mm to 500mm range covered with your lenses, and you put the 1.4x on your 500mm, and you still need more reach then the crop body is a benefit. With all of your other lenses if you can frame fully and properly the 5D II sensor would be putting more pixels on the subject than the 7D sensor.

But, all bodies AF systems are not equal and not all have the same options. In the 5D II vs the 7D race the 7D AF system would be far superior for wildlife and sports.

While we got sidetracked from the OP's origional question, to me the answer is that the OP would benifit more from the superior AF system of the 7D than a full frame 5D II, provided wildlife is the driving factor.
« Last Edit: October 22, 2012, 04:43:22 PM by PackLight »

jrista

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Re: do crop sensors really add reach?
« Reply #115 on: October 22, 2012, 04:59:08 PM »
While we got sidetracked from the OP's origional question, to me the answer is that the OP would benifit more from the superior AF system of the 7D than a full frame 5D II, provided wildlife is the driving factor.

Totally agree, with the added benefit that the 7D will produce more detailed photos on top of the better AF.
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dlleno

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Re: do crop sensors really add reach?
« Reply #116 on: October 22, 2012, 05:31:26 PM »
While we got sidetracked from the OP's origional question, to me the answer is that the OP would benifit more from the superior AF system of the 7D than a full frame 5D II, provided wildlife is the driving factor.

Totally agree, with the added benefit that the 7D will produce more detailed photos on top of the better AF.

provided distance limited wildlife is the driving factor, and where the OP as met the optimum conditions including glass, light,  and support to take advantage of the 7D resolution. 

jrista

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Re: do crop sensors really add reach?
« Reply #117 on: October 22, 2012, 07:24:13 PM »
While we got sidetracked from the OP's origional question, to me the answer is that the OP would benifit more from the superior AF system of the 7D than a full frame 5D II, provided wildlife is the driving factor.

Totally agree, with the added benefit that the 7D will produce more detailed photos on top of the better AF.

provided distance limited wildlife is the driving factor, and where the OP as met the optimum conditions including glass, light,  and support to take advantage of the 7D resolution.

My argument about getting new L-series glass was to realize the maximum potential resolution the 7D has to offer, which was...what, 2.21x times more than the 5D II. Even without perfect glass, the 7D is still going to resolve more detail than the 5D II, just not necessarily 121% more.
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Re: do crop sensors really add reach?
« Reply #117 on: October 22, 2012, 07:24:13 PM »