[traderdrew]

Nope, any picture you can take with FF, you can take with APS-c. There may be difference in the out of focus areas but you can take the picture.
Because of the practical limitations of FF sensors, ei, less pixel density... you can always achieve more magnification on the area covered by the crop sensor using APS-c.

My buddy has one of those Canon point and shoots with an 850 mm equivalent lens... he got images of a Merlin with his little portable do everything camera than I got with my K-5 and A-400. It sucks... but bigger isn't always better. Deal with it.

I think what you are saying is his point and shoot did a better job. I had experienced something similar until I purchased the Sigma 500mm F/4.5. Those little point & shoots have the ability to focus better on a Merlin. Merlins typically don't let you get close and so he had to use maximum magnification with the P&S camera. I do like the 1.5x crop for that extra reach. Still I could use some focus peaking because I like good photos of Merlins also.

Still my trained eyes can see a problem or two with Merlin images produces with those little cameras. The images just don't look the same as if it was photographed with an 800mm F/5.6 lens.

[Rondec]

Nope, any picture you can take with FF, you can take with APS-c. There may be difference in the out of focus areas but you can take the picture.
Because of the practical limitations of FF sensors, ei, less pixel density... you can always achieve more magnification on the area covered by the crop sensor using APS-c.

My buddy has one of those Canon point and shoots with an 850 mm equivalent lens... he got images of a Merlin with his little portable do everything camera than I got with my K-5 and A-400. It sucks... but bigger isn't always better. Deal with it.

At least for Pentax, there are not lenses that are the equivalent of 35mm f1.4 or 24mm f1.4 or 14-24 f2.8 on full frame. That's not to say you can't find lenses with the same field of view as these lenses have.

[normhead]

At least for Pentax, there are not lenses that are the equivalent of 35mm f1.4 or 24mm f1.4 or 14-24 f2.8 on full frame. That's not to say you can't find lenses with the same field of view as these lenses have.

And most Pentax users seem to be fine with that. Most of us don't live our lives in a studio. Carrying a 14-24 2.8 is problematic. My buddy Brian brought his on our canoe trip, but he very rarely had it with him when we traveled. I have many possibly marketable images he didn't get on his D800 because the lens was deemed too heavy to carry over rough terrain. he would have had to leave something more useful back at camp. Theory means nothing if it's not functional. A theoretical concept isn't useful if their are physical factors that keep it from being put into practice.

In this case, I have 8-16 images, that came out awesome, he doesn't have 14-24 images because it was too heavy.

Eat you heart out Brian... he's got an FF, but I've got an image.

[Andi Lo]

And most Pentax users seem to be fine with that. Most of us don't live our lives in a studio. Carrying a 14-24 2.8 is problematic. My buddy Brian brought his on our canoe trip, but he very rarely had it with him when we traveled. I have many possibly marketable images he didn't get on his D800 because the lens was deemed too heavy to carry over rough terrain. he would have had to leave something more useful back at camp. Theory means nothing if it's not functional. A theoretical concept isn't useful if their are physical factors that keep it from being put into practice.

In this case, I have 8-16 images, that came out awesome, he doesn't have 14-24 images because it was too heavy.

Eat you heart out Brian... he's got an FF, but I've got an image.

Really nice image, makes me want to go there

You bring a really good point that APSC has the size weight advantage. A camera at home really means lost images. This is why the DA lims are so great! I personally also still use APS-C for UWA, as I dont need the background to be blurry for most UWA shots.

Not everyone lives at f/8-f/16 though. My exif shows that I mostly live at f/2-f2.8, that's just the type of images I deal with the most. D800 is also still the only affordable option to achieve 36mp without pano for people that can use the extra resolution.

In Brians' case since he probably doesnt need the f2.8, he can use the 16-35 or heck, Samyang 14mm, which is an awesome lens for with excellent ROI. 14-24 is not the only FF UWA in existence. The world is chock full of cheap FF UWA options. Sigma 14mm, Sigma 12-24, the infinite variations of Promaster 17-35, Tokina 20-35, Canon 17-40 (also amazing value lens at f/8), etc etc

Also Brian needs a Cotton Carrier.
http://buy.cottoncarrier.com/cotton-carrier-camera-system-p/124rtl-d.htm

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Last edited by Andi Lo; 10-25-2013 at 09:56 AM.

[normhead]

Really nice image, makes me want to go there

. My exif shows that I mostly live at f/2-f2.8, that's just the type of images I deal with the most.

Cotton Carrier Camera Systems ? Camera Vest Carry-Lite StrapShot Steady Shot

I hope Pentax brings out a Pentax FF with 36 MP just for you. I'm the opposite, less than 1% of my images are shot from 2-2.8. It's the outdoor thing. And I've actually just gone to a Lowenpro belt and harness. Traveling in the bush, having an exposed camera is a recipe for disaster. The Lowenpro has a holster big enough for my 60-25, and a couple of attached pouches for the -8-16 and 18-135 or Tamron 17-50, depending on weather or and whether or not there's a possibility of rain. But just with that stuff, by the end of a long hike, I'm tired. I recently compared K-5 IIs images with an Olympus E-M5, and thought, "I could go even lighter and get slightly better IQ". But my K-3 is coming so, I probably won't investigate further.

[BrianR]

It seems to me this is the best answer to my question.

So it seems the DOF calculator I linked in the first post here, "assumes" as you say that the final print size is the same. Therefore it is cropping the FF image to produce the same size image that a crop sensor produces in order to arrive at those calculations?

The calculator isn't cropping the FF image, no. You're getting a different image if all you change is the format but leave distance and focal length the same, eg. a tight shot of someones face on the APS-C will become a head and shoulders shot on the Full Frame since focal length and distance to the subject remain the same. The pictures are then both printed at 8x10, and to get to the 8x10 size you need to enlarge the image from the APS-C sensor 1.5 times more than you need to enlarge the FullFrame sensors image and stuff gets less in focus the more you enlarge it.

I should have included pictures from the start, this hopefully will help clarify. It's a bit of a cheat, since the image on the left is from my k100d, but it illustrates what's happening.

Imagine you take a photo of a wet, sloppy, smiling dog at 50mm, f4, using your full frame camera. This is the image on the left. Swap out to an APS-C camera (which has a sensor 2/3 the size of a 'full frame'), but stay in the same spot and leave the lens and aperture at the same settings. Do this again with our hypothetical camera with a sensor size 1/3 that of full frame (the more extreme the sensor size difference, the easier the difference is to see). Now send the files to the lab to print out 8x12's, or just look at them on your screen at the same size.

On my screen, the nose looks to be pretty much in focus on the Full Frame version. Less so on the 2/3 Full Frame, and definitely distressingly out of focus at 1/3 Full Frame. All that's changed here is the smaller sensor needs to enlarge the dogs face more to get the same final print size. This makes the blur that already exists on the nose less and less tolerable since this extra enlargement magnifies it.

[Andi Lo]

I hope Pentax brings out a Pentax FF with 36 MP just for you. I'm the opposite, less than 1% of my images are shot from 2-2.8. It's the outdoor thing. And I've actually just gone to a Lowenpro belt and harness. Traveling in the bush, having an exposed camera is a recipe for disaster. The Lowenpro has a holster big enough for my 60-25, and a couple of attached pouches for the -8-16 and 18-135 or Tamron 17-50, depending on weather or and whether or not there's a possibility of rain. But just with that stuff, by the end of a long hike, I'm tired. I recently compared K-5 IIs images with an Olympus E-M5, and thought, "I could go even lighter and get slightly better IQ". But my K-3 is coming so, I probably won't investigate further.

I dont need 36mp, never said that I did, My clients dont ever print that big. I hope pentax comes out with a 12mp FF that has an pentax LX viewfinder, clean ISO 25600, and K10D rendering, under 300grams, that would be the ultimate FF walkaround camera for me.

Use whatever works that you can get today, right? I still use APSC myself, but claiming that no photographer can benefit from FF is fallacy- and so is claiming that it will be better for everyone to switch to FF, which I hope I've been careful enough not to do.

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Last edited by Andi Lo; 10-25-2013 at 10:19 AM.

[BrianR]

I have many possibly marketable images he didn't get on his D800 because the lens was deemed too heavy to carry over rough terrain. he would have had to leave something more useful back at camp.

It's always a compromise. Someone more determined, or with the cash to hire a sherpa, could have lugged a large format film camera and shot right beside you and had an image that beats yours from a technical standpoint. Someone else could have shot with an iphone and kept room in their pack for a six pack of beer.

All photographers can do is choose their compromise and try not to throw empty beer bottles at people whose priorities are different. I totally get people who want a Pentax FF and I also hope they get what they want. The compromise to my wallet is currently more than I could manage at the moment.

[tuco]

...
In this case, I have 8-16 images, that came out awesome, he doesn't have 14-24 images because it was too heavy.

Those big pro zooms from Nikon tend to be lenses you carry because you need to not because you want to. That guy really should look into getting a wide prime if he's hauling that much gear. I'm not a super wide angle lens user and find my Zeiss 21/2.8 is wide enough for me 98% of the time on my FF. I take it he's not a young buck anymore because I've hauled 10 times more weight around in LF gear up mountains that I could not really do today. I'd consider what he was hauling a piece of cake back then.

[normhead]

On my screen, the nose looks to be pretty much in focus on the Full Frame version. Less so on the 2/3 Full Frame, and definitely distressingly out of focus at 1/3 Full Frame. All that's changed here is the smaller sensor needs to enlarge the dogs face more to get the same final print size. This makes the blur that already exists on the nose less and less tolerable since this extra enlargement magnifies it.

Now that's what you've got messed up.

FIrst of all, if your dogs nose was in sharp focus and you had a good sensor, it would still be in sharp focus on the enlarged image. I have foveon images taken with my DP2M, that look just as good enlarged to 1:1 as they do small. So that is defintiely a technical shooting issue, not per se a function of enlargement. Second. If your crop image was taken with a 24 MP crop sensor, you'd have about 30% more resolution in the crop image.

Your comparison is accurate in that for DoF we are discussing at what point the circles of confusion become visible. And that requires a lot more work than what you're doing here. So as long as the images are sharp, as in a circle of confusion less than one pixel, sharpness is determined by the number of pixels in the frame. In that case, APS-c kills any FF less than one with at least 50 MP, and those (like unicorns) don't exist.

At some point you would have to do research to find out at what point the circles of confusion become visible in your print. There are many factors in this as well. My own meager fooling around deduced that at 3000 pixels across, a K-5 image was indestinguishable from a D800 image on a 92 pixel per inch screen. That translates to roughly a 30 inch print , printed at 100 dpi. At some point the amount of magnification of the circles of confusion become more of a factor. So what I'm saying is , at 1:1 magnification of the image, that is the FF image is 33x22mm, you wouldn't see the difference in size of the circles of confusion. You have to magnify quite a bit before the difference in DoF even becomes visible. I'd assume once the DoF becomes visible at some point you would start measuring the distance in DOF, but what the defining parameters would be and how they would be applied would still have to be determined, and the results would depend in part on the visual accuity of the viewer. So honestly I'm not sure what you hope to gain from this. ALl you really need to know is you can achieve narrower DoF with an FF camera and with an equivalent lens wider DoF with an APS-c camera. If you are limited by not getting narrow enough DoF, then shoot full frame. If you are a hyper focal shooter and are limited by too narrow DoF, shoot APS-c. Beyond that, making precise calculations of DOF to determine the DOF on various systems is pretty much a waste of time. The resulting measurements won't be accurate enough to justify the math. You learn a lot more from trial and error.

To me, the biggest factor in narrow DoF images is, how smooth the bokeh is, and that tends to be a factor of how corrected the lens is,and has nothing to do with focal length or aperture.

[ElJamoquio]

Honestly, any photo you can take with APS-C, you can also take with full frame, but not the reverse.

Bingo. Plus you get the better sharpness of the FF, and usually better color, too.

Mrs. ElJamoquio was taking pics with her new Ricoh APS-C and about cried when she saw the same pics from the D600. I actually didn't think they were THAT different.

[noser]

This whole DoF on FF vs APS-C thing comes up a lot, but in the inevitable discussion of the mathematical equivalent "one stop difference" tends to auger down into the details and ignore that at different focal lengths you WILL get different images even if you think you are getting an identical image in terms of DoF, because the FoV must change.

Consider these comparison images on Steven Eastwoods site:
Stephen Eastwood|Beauty and Fashion Photographer | Tutorials

Yes, you can get similar images with different apertures, but distortion and working distances will be different.

In my experience of comparing my 50mm's at f/2.8 to my Sigma 30mm at f/1.4 (both on the K-5) the distortion is annoyingly noticeable for tighter portraits using the 30mm. The trade off becomes a longer working distance to use the 50's, but I don't get the environmental capture of a wider fov.

Now for full body (standing or sitting), the 50's are just about perfect on APS-C; very much like an 85mm on FF, but I can't replicate 85/1.4, since my 50/1.2 is noticeably softer @ 1.2 (and harder to nail focus with). But really for those distances f/2.8 or f/4 is probably more appropriate for the subject, it's just not as bokeh-licious.

I'm getting to really like the closer working distances of FF at longer FL's so I don't have to yell at my clients because I have to stand further back to use the same FL's to avoid the fun-house effect.

Hence ... "Where is my FF, Pentax?!?!?"

[normhead]

I already addressed, that and explained exactly why it's not true. This guy must have me on ignore. Oh well, his loss.

In my experience of comparing my 50mm's at f/2.8 to my Sigma 30mm at f/1.4

Well actually the stops go 1, 1.4, 2, 2.8, 4 etc., so 2.8 to 1.4 is 2 stops... if you can't tell the difference between one stop and two stops the whole conversation is moot. One stop is the difference between APS-c and FF.

[vonBaloney]

FIrst of all, if your dogs nose was in sharp focus and you had a good sensor, it would still be in sharp focus on the enlarged image.

But with DOF, we aren't talking about areas of sharp focus. There is only ever one point (or plane of distance) that is ever in sharp focus, and yes that will be in focus at any size. EVERY OTHER POINT is out-of-focus to some degree, but we still consider some of those areas to be in the "depth of field" of *acceptable* focus GIVEN a certain print size, etc etc. So his example of a slightly out-of-focus point becoming less and less acceptable (moving from being in the DOF to out of the DOF) as it is magnified is right on the money.

[BrianR]

FIrst of all, if your dogs nose was in sharp focus and you had a good sensor, it would still be in sharp focus on the enlarged image.

No matter what sensor or aperture or lens you use, if you focused on the eyes, you can enlarge the print to the point where the tip of the nose will be out of focus (assuming you've fixed your definition of 'out of focus'). Note that in my example the eyes are in sharp focus as that's what I focused on, and they stay in sharp focus (for some definition of 'sharp'). The nose will at best be 'acceptably not too far out of focus' since everything not in the plane of focus is out of focus to some extent. Circles of confusion just measure how far out of focus stuff is, and the DoF you report depends on just how far out of focus we're OK with. That was the point here, the more you enlarge an image they shallower the DoF becomes, and that's exactly what the OP's calculator was reflecting.

And that requires a lot more work than what you're doing here. So as long as the images are sharp, as in a circle of confusion less than one pixel, sharpness is determined by the number of pixels in the frame.

Is that really the definition you want to take for 'sharp'? Do you understand how the DoF equations are laid out?

At some point you would have to do research to find out at what point the circles of confusion become visible in your print.

There are actually pretty well accepted values for this already. See the link you gave https://www.pentaxforums.com/forums/pentax-full-frame/240468-depth-field-ffs-aps-c-3.html