[dadipentak]

Those are valid points, Bossa. I'm more like Norm in terms of approach but I can see how this might be a useful option for others.

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Last edited by dadipentak; 10-13-2013 at 10:04 AM.

[bossa]

To give an idea of that extra depth of detail with the D800E over the K-5 I've uploaded a few screen captures from Lightroom.

K-5 & DA*200mm @ f/2.8 versus D800E & AF-S 300mm @ f/4. The images look almost identical at this level. Notice the shutter speed differential as well. The DA*200 has a much faster shutter speed in the same lighting conditions for the same DOF (f/2.8vf/4) and ISO settings.


100% magnification reveals the DA*200mm @ f/2.8 is not as sharp as the AF-S 300mm @ f/4 and there's that extra zoom-in on the FF


With both lenses @ f/4 the DA*200mm catches up somewhat but then the DOF is no longer the same

[audiobomber]

I still don't see what the advantage is over using the whole frame and then cropping afterwards....you don't get any more AF points, and they're not in any different positions, the deeper buffer is the only physical advantage I can see.

That's the way I see it too. At first the 1.3X crop looked interesting, but once I thought about what it is, it seems like no advantage at all. I think Nikon implemented it to make their buffer look less compromised.

[Barry Pearson]

Since in many cropped images, framing is an issue, I'm not sure I'd use that. I generally want the full frame, giving me more opportunity to change my crop afterwards. To me one of the biggest advantages of 24 MP is the ability to crop after shooting, an extra 1000 pixels of croppable image. It would be interesting to hear from an D7100 users if they actually use that mode and why. To me, if Pentax asked me if they'd should implement that mode, I'd probably say don't waste the resources. Cropping is just one of those things better done with more information, not less. Especially in BiFs where the subject often isn't n the same spot in the finished image it was in when you pressed the shutter release.

But hey, maybe someone will explain what situation they use this feature in. I certainly don't see how for myself it could make up for 2 stops less AF capability in the low end.

I would have thought that the only real use for in-camera cropping from a larger image circle is where careful composition is possible! And even then - why bother, since you are not taking many photos so their size doesn't matter?

I fully agree with you - for action of any type, keep as many pixels as possible, both to allow for errors at taking time, and for composition in post-processing.

(Edit: I shoot only DNG. Perhaps different principles apply when shooting low resolution JPEGs).

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Last edited by Barry Pearson; 10-13-2013 at 04:04 AM.

[Rondec]

That's the way I see it too. At first the 1.3X crop looked interesting, but once I thought about what it is, it seems like no advantage at all. I think Nikon implemented it to make their buffer look less compromised.

I agree. There is no purpose to using such a feature unless it speeds up your frame rate or prevents the buffer from being killed. Pentax has a new processor which seems to deal well with the larger files and so this won't be an issue on the K3.

[audiobomber]

When I first read about the D7100 16mp crop, I thought it would finally show m4/3 shooters what crop means. Unfortunately they still don't get it.

"Look how small my Olympus 300mm lens is compared to a 400mm lens for APS-C."

[RonHendriks1966]

According to Imaging Resource: "When in 1.3x crop mode, the camera displays an inset frame guide to indicate the smaller size image. ... It's nice in that it not only helps you with composition, but it also serves as a reminder that 1.3x crop mode is activated ... The downside I found is that the rest of the frame is still in view"

Pic related, from the D7100 brochure PDF:



In this mode, the advantage for tracking AF is apparent, in that the D7100's 51 focus points cover almost the entire shooting frame.

From these descriptions, I guess for Pentax to implement this feature in a similar way would require more than just a firmware fix. Since the K-3 viewfinder is optical, the D7100's visible 'DX-crop' framing guide and icon in the viewfinder would require hardware changes to the viewfinder overlay (unless Pentax anticipated introducing this feature at some future point, and have already accomodated it in some not-visible way).

The K-3 AF would probably have no problems working with a 'DX crop' mode though, without any alterations, since all the 27 K-3 focus points are pretty much bunched together in the frame centre, just like the D7100's.

So in 1.3x crop DX you can also buy the Olympus!

[bossa]

I would have thought that the only real use for in-camera cropping from a larger image circle is where careful composition is possible! And even then - why bother, since you are not taking many photos so their size doesn't matter?

I fully agree with you - for action of any type, keep as many pixels as possible, both to allow for errors at taking time, and for composition in post-processing.

(Edit: I shoot only DNG. Perhaps different principles apply when shooting low resolution JPEGs).

Check out the prices of 600mm Nikon lenses and then have another think about that statement.

[normhead]

Those are cool examples Bossa, but what would be more relevant would be K-5 image, and a D800 crop image both shot with the same focal length. My expectation would be that they'd be pretty much the same. Using a K-3, I'd expect the k-3 image to be better than the D800 crop. The point being, in a situation where you are going to crop anyway, you are better off using a crop sensor.

The situations where that will be true are many. Wildlife that you can't get close to. Macro. is another. My longest lens is 400mm. That will be true whether using FF or APS-c. For most images a K-3 will give me about 25% more resolution than a D800 type FF.. You could go to a 600mm lens with a D800 and get better results, but there isn't a 600mm lens on the planet I'd want to carry. So for me, the A-400 is the practical cut off in terms of useful lenses. In an AF lens it would probably be a DA*300.

[Rondec]

Those are cool examples Bossa, but what would be more relevant would be K-5 image, and a D800 crop image both shot with the same focal length. My expectation would be that they'd be pretty much the same. Using a K-3, I'd expect the k-3 image to be better than the D800 crop. The point being, in a situation where you are going to crop anyway, you are better off using a crop sensor.

The situations where that will be true are many. Wildlife that you can't get close to. Macro. is another. My longest lens is 400mm. That will be true whether using FF or APS-c. For most images a K-3 will give me about 25% more resolution than a D800 type FF.. You could go to a 600mm lens with a D800 and get better results, but there isn't a 600mm lens on the planet I'd want to carry. So for me, the A-400 is the practical cut off in terms of useful lenses. In an AF lens it would probably be a DA*300.

True. When I shoot wildlife, I am cropping my APS-C photos already and if I went full frame, I still don't think I would want to shoot longer than 300-ish mm. This makes high pixel density APS-C a good option for wildlife.

[bossa]

Those are cool examples Bossa, but what would be more relevant would be K-5 image, and a D800 crop image both shot with the same focal length. My expectation would be that they'd be pretty much the same. Using a K-3, I'd expect the k-3 image to be better than the D800 crop. The point being, in a situation where you are going to crop anyway, you are better off using a crop sensor.

The situations where that will be true are many. Wildlife that you can't get close to. Macro. is another. My longest lens is 400mm. That will be true whether using FF or APS-c. For most images a K-3 will give me about 25% more resolution than a D800 type FF.. You could go to a 600mm lens with a D800 and get better results, but there isn't a 600mm lens on the planet I'd want to carry. So for me, the A-400 is the practical cut off in terms of useful lenses. In an AF lens it would probably be a DA*300.

When you require a composition then the equivalent lens is the fair comparison but you're obviously correct when saying that the crop sensor has the advantage where pixel density is greater.

As you say, were the focal lengths on both bodies (d800 & k-5) the same, the cropped output would look the same when cropped to 100% and this is why I'm interested in a 24MP APS-C camera (for telephoto work). I'm not interested in lugging a 600mm lens around either but I'm even more disinterested in spending 10 grand on one.

PS> The 1.3x crop mode on the D7100 is important when you want to retain some composition and a standard 15MP resolution file. The effective focal length for a 400mm lens in that mode is 800mm. The Nikon 800mm lens costs around $20,000 so I think a cheap 400mm in that crop mode and at that resolution is quite an acceptable route to go.

[Barry Pearson]

Check out the prices of 600mm Nikon lenses and then have another think about that statement.

What has that got to do with what I said?

I said "I would have thought that the only real use for in-camera cropping from a larger image circle is where careful composition is possible!"

In other words, I'm talking about the case where someone is using a lens with a large image circle. Then discarding some of that image circle, (in effect, wasting some of the price of that lens), by throwing away pixels, only makes sense if there is confidence those pixels won't be needed. Hence where careful composition is possible.

Obviously I'm not saying "buy an expensive lens"!

[bossa]

What has that got to do with what I said?

I said "I would have thought that the only real use for in-camera cropping from a larger image circle is where careful composition is possible!"

In other words, I'm talking about the case where someone is using a lens with a large image circle. Then discarding some of that image circle, (in effect, wasting some of the price of that lens), by throwing away pixels, only makes sense if there is confidence those pixels won't be needed. Hence where careful composition is possible.

Obviously I'm not saying "buy an expensive lens"!

I'm not arguing against that POV at all but merely advocating a budgetary response to not being able to afford $10,000-20,000 lenses when an acceptable 15MP standard format (1.5*1.3x crop mode) exists. Cropping for composition after the fact is obviously an acceptable way to edit images, just as is pre-defining your limitations is conducive to developing skills in the field.

[Barry Pearson]

I'm not arguing against that POV at all but merely advocating a budgetary response to not being able to afford $10,000-20,000 lenses when an acceptable 15MP standard format (1.5*1.3x crop mode) exists. Cropping for composition after the fact is obviously an acceptable way to edit images, just as is pre-defining your limitations is conducive to developing skills in the field.

Are you talking about a 1.3x crop mode on an FF camera? Yes, that could be useful if someone with such a camera wants to use a lens whose image circle doesn't cover the entire FF sensor.

I am talking about the K-3 and any future APS-C camera. Pentax lenses, and lots of others, have image circles that cover that sensor. Having a 1.3x crop mode on such a camera involves throwing away pixels with part of the image on them. That is only safe if the image has been composed so that those discarded pixels only contain part of the image that the photographer certainly doesn't want. Hence where the photo is carefully composed.

[bossa]

Are you talking about a 1.3x crop mode on an FF camera? Yes, that could be useful if someone with such a camera wants to use a lens whose image circle doesn't cover the entire FF sensor.

I am talking about the K-3 and any future APS-C camera. Pentax lenses, and lots of others, have image circles that cover that sensor. Having a 1.3x crop mode on such a camera involves throwing away pixels with part of the image on them. That is only safe if the image has been composed so that those discarded pixels only contain part of the image that the photographer certainly doesn't want. Hence where the photo is carefully composed.

The D7100 has it's own 1.3x crop mode (just as the D800 has a 1.5x crop mode) which works out to be 1.3*1.5 (1.95) of a FF sensor. You end up with a 15MP file size and an effective 2x crop factor. A cheap $1200 300mm lens suddenly has the FOV (and a usefull file size) of an expensive 600mm lens. Obviously it would be much better to have a $10,000 f/4 600mm lens on a FF but that's another story as far as money and weight goes.