DX vrs. FX

[oregondaddyof2]

All this talk about the FX cameras is making me want to go put away my D60 and go upgrade to a D700... I thought I wanted to upgrade to the D300, but not anymore...

 

[Gdad]

You obviously know a heckuva lot more than me, but isn't VR useful in situations where ISO and aperture will not help? For instance, if I want to use a slightly longer shutter speed to show motion in the subject, VR will correct my slight camera shake (preventing the entire image from being crap), whereas it won't do anything to the subject. Perhaps the situations for using this are few and far between, but it's still nice to have (or am I overlooking something?)

Yeah I suppose that would be an example I had not considered. I don't know why Nikon chose not to include vr on their normal to wide angle pro level zooms- certainly no matter how 'good' they are including vr could never hurt except maybe to make them even less affordable than they already are.

 

[Evad]

Now Dave- as for the original question- I will tell you that I absolutely love Full Frame. To me personally- the jump from DX to FX was a quantum leap almost as significant as moving from a P&S to a DSLR. I have said this before but I bought it pretty much for the ISO and the viewfinder. And those things are great but now what I really love is that the FX sensor just has a certain look and feel to it. I can't really put my finger on it but I know every lens I had in my bag got way better overnight. Not necessarily sharper- I don't do test shots on brick walls or care about charts or graphs- they just got better- yummier- hard to explain but it's there. And I like old lenses- mostly primes- because they have distinct personalities which I appreciate- unlike most of the modern computer designed zooms which all have the same clinical sort of look to them- and shifting to FX more than anything was like turning a spotlight on that. Something that was there all along- just amped up on FX. I have no idea if that will make sens but- well hey- you asked.

Yummier, now that's technical term I can understand......

Believe it or not Jeff your explanation makes perfect sense. This was also I sort of imagined the difference would be without getting all technical, I just wanted some of you pros to try explain it to me. My budget at this time certainly would not allow such an upgrade to an fx body but if things change I can now go into it with much more knowledge then I had before.

Again thank you all for weighing in on this subject. You can always count on the dis photoboard set one straight on a particular subject matter.

I was also wondering if one of you pros could post a pic taken with an fx sensor that just couldn't be done on a dx camera. Thank you!!

 

[Groucho]

I'm going to put in the opposing viewpoint here. (Apologies in advance, as I look back at this, I am rambling a bit. A little overtired I guess. )

Well, not opposing, but not as much. I don't think the FF thing is nearly as important as some have made it out to be. Also, I think we need to separate out body advantages from sensor advantages, since FF can be had with wildly different megapixel levels.

First off - yes, absolutely, FF can be better at high ISO - but we mainly see that with Nikon's 12mp sensor. Check out the 24.6mp Sony A900 - it's high-ISO noise levels are pretty similar to what you'll find in DSLRs with 12mp sensors.

FF does not automatically equal better image quality. The Online Photographer has said: "Ultimately, I suspect the image quality (IQ) of the K20D is better than that of the Nikon D700" - this is not a slight against the D700 in any way (they love it) but the point is that, when you look at the final result, you are not guaranteed a better or sharper photo.

IMHO, the advantages of the APS-sized sensor are size, weight, and more reach at the tele end. Size/weight does not mean just the camera - the 50-135mm F2.8 for APS cameras (available as a Tokina for non-Pentax DSLRs) is equivalent to a 70-200mm F2.8 on a FF - and it weighs about half as much. (Slightly less than half compared to Canon's, slightly more than half compared to Nikon's.)

The advantages of a FF body are obviously the relatively huge viewfinder... and, well, that's about it. No, I'm not being fair - there are lens advantages - older lenses are designed to perform well on film so may work better on a FF sensor than a crop-sensor. One big advantage that I haven't seen mentioned is wide-angle distortions - you're a lot more likely to get purple fringing and other aberrations on a crop-sensor camera ultrawide or fisheye lens than an equivalent FF lens.

Sensor-wise... well, I'm not a big fan of the ultraresolution sensors like in the A900. 24.6mp is impressive but at what cost? You get much worse noise levels than Nikon's benchmark 12mp sensor, you need higher quality lenses to get the best results, and you'll never see those extra details unless you print large posters or do extreme cropping. Meanwhile, you're left with massive files that choke your PC.

IMHO 12-16mp is a "sweet spot" for DSLRs, I see little reason to go above that. Were I a Canon shooter, I'd be somewhat bummed at their choice of a 21mp sensor - I'd rather have less mp and another usable stop of ISO.

I think Nikon really was smart to stick with 12mp for their full-frame sensor. It meant at least two stops better noise levels than crop-sensor cameras, plus lenses don't need to be as good to get solid results, since the sensor isn't working them as hard. Would the D3 and the D700 be so impressive if they had, say, 24mp sensors but only slightly better (or not at all) high-ISO noise levels? I rather doubt it.

OK, I've rambled, let me see if I can sum up so if you're smart, you'll probably ignore everything I just wrote and skip ahead to here!
Crop-sensor: Smaller, lighter, IQ can be just as good
Full-frame: larger, brighter viewfinder, more DoF, better ultrawide performance, potentially better high-ISO noise levels
Full-frame low-megapixel: much better high-ISO noise levels

If you are using a crop-sensor DSLR and want to experience full-frame goodness on the cheap - it's easy, just pick up a film camera and go to town. Pair it with a quality scanner like the Nikon Coolscan and voila, ~25mp images; just don't expect high ISO levels to be all that impressive!

One other quick note: I checked my sensor sizes graph and a FF sensor has about 2.34x more surface area than an APS sensor. That would mean that a 12mp sensor on APS should perform similar to a 28mp sensor on FF. Going the other way, that would mean that you could get similar high-ISO noise performance on an APS sensor with about 5.1mp. I for one would not be opposed to a 6mp APS-sensor low-light master.

 

[MarkBarbieri]

First off - yes, absolutely, FF can be better at high ISO - but we mainly see that with Nikon's 12mp sensor. Check out the 24.6mp Sony A900 - it's high-ISO noise levels are pretty similar to what you'll find in DSLRs with 12mp sensors.

One must be careful to do a fair comparison. If you take a Sony A900 image and intelligently reduce the resolution to 12mp, you get much less noise. This is the same phenomena that has dark ride pictures looking ugly at a pixel level but looking nice when displayed 800x600 in the forum.

For a much better explanation of this, read the article Contrary to conventional wisdom, higher resolution actually compensates for noise. Another interesting article is The paradoxical evolution of sensor SNR over time. It shows that the S/N ratio for DSLRs has actually declined 1db over the last several years but that the increase in resolution has caused the effective S/N ratio has improved 2.5db.

FF does not automatically equal better image quality. The Online Photographer has said: "Ultimately, I suspect the image quality (IQ) of the K20D is better than that of the Nikon D700" - this is not a slight against the D700 in any way (they love it) but the point is that, when you look at the final result, you are not guaranteed a better or sharper photo.

IMHO, the advantages of the APS-sized sensor are size, weight, and more reach at the tele end. Size/weight does not mean just the camera - the 50-135mm F2.8 for APS cameras (available as a Tokina for non-Pentax DSLRs) is equivalent to a 70-200mm F2.8 on a FF - and it weighs about half as much. (Slightly less than half compared to Canon's, slightly more than half compared to Nikon's.)

It is certainly true that not every camera with a larger sensor produces better images than every camera with a smaller sensor. Sensor size does come with distinct advantages and disadvantages. The sweet spot for each photographer will be different and ranges all the way from cell phone cameras with tiny sensors to large digital backs. FF is just another stop along the way.

The advantages of a FF body are obviously the relatively huge viewfinder... and, well, that's about it. No, I'm not being fair - there are lens advantages - older lenses are designed to perform well on film so may work better on a FF sensor than a crop-sensor. One big advantage that I haven't seen mentioned is wide-angle distortions - you're a lot more likely to get purple fringing and other aberrations on a crop-sensor camera ultrawide or fisheye lens than an equivalent FF lens.

You know better than that. The big advantage of FF is that it is a larger sensor and can gather more light. It can use that for higher S/N ratios, higher resolutions, less aggressive AA filters, etc. It's not a magical ideal size, it's just bigger than APS-C sized sensors. The IQ advantage of FF over APS-C is roughly similar to the IQ advantage of APS-C over the Olympus 4/3 sized sensors.

Sensor-wise... well, I'm not a big fan of the ultraresolution sensors like in the A900. 24.6mp is impressive but at what cost? You get much worse noise levels than Nikon's benchmark 12mp sensor, you need higher quality lenses to get the best results, and you'll never see those extra details unless you print large posters or do extreme cropping. Meanwhile, you're left with massive files that choke your PC.

As stated above, the S/N difference isn't that big once you do an apples to apples resolution comparison. The advantages of higher resolution have been stated a million times in the past when each new generation of higher resolution sensors brings out a flood of complaints that it is too much and that 3, 6, 8, 10, 12, 15 or whatever the prevailing norm is the ideal resolution. Higher resolution brings some small costs (larger file sizes and longer processing times). It brings benefits of finer detail resolution, increased ability to crop, and the ability to average pixels to trade resolution for increased IQ.

IMHO 12-16mp is a "sweet spot" for DSLRs, I see little reason to go above that. Were I a Canon shooter, I'd be somewhat bummed at their choice of a 21mp sensor - I'd rather have less mp and another usable stop of ISO.

Here's the sweet spot argument again. It seems to be a natural tendency among shooters not contemplating an immediate upgrade to consider their current resolution as ideal. Personally, I'm thrilled with the 21mp sensor resolution on my 5D. When I want a lower resolution, I shoot in sRAW and get a 10mp FF sensor.

If you want a good comparison of the characteristics of different sensors and cameras, check out the Image Quality Database. You can easily see the correlation between sensor size an IQ there. The top rated sensor is the Phase One P65. Next Nikon full frames (DX3, D3, and D700) with the Dx3 being significantly better. They are followed by the Canon full frames and the Sony full frame. APS-C sensors don't appear until you get down to the Nikon D90. The Olympus 4/3 sensors are still further down the list.

Once again, I'm not saying that FF is ideal. It's just another stop along the scale of improving IQ with increasing sensor size. I suspect that as more camera companies move to FF, their fans will change their opinions about ideal sensor sizes. It has certainly happend with Nikon and Sony shooters that I know that were once dismissive of FF DSLRs.

 

[KAT4DISNEY]

IMHO, the advantages of the APS-sized sensor are size, weight, and more reach at the tele end. Size/weight does not mean just the camera - the 50-135mm F2.8 for APS cameras (available as a Tokina for non-Pentax DSLRs) is equivalent to a 70-200mm F2.8 on a FF - and it weighs about half as much. (Slightly less than half compared to Canon's, slightly more than half compared to Nikon's.)

I'm a little confused on exactly what the difference is between the APS-C and FF sensor - relating to how it does the "zoom". To probably over simplify from what I've read it seems that the APS-C crops the photo that you take, thus giving the appearance of a longer focal length. Since it's often referred to as a crop factor that made sense to me. I.e., 200mm is 200 mm but the APS-C sensor will only use the center portion of the frame. This also gives an advantage to using FF lenses b/c the APS-C sensor is using the sweet spot of the lens. However, in using a FF camera you can achieve the same thing - but just have to do the cropping yourself. And with a FF you will have the advantage of the larger sensor with greater light gathering capabilities - and depending on the camera greater resolution providing finer detail.

Groucho's comment about more reach seems to negate what has been my understanding.

OK - happened to run across this though I wasn't looking. It answered my own question! http://www.digital-slr-guide.com/full-frame-digital-slr.html

 

[Groucho]

One must be careful to do a fair comparison. If you take a Sony A900 image and intelligently reduce the resolution to 12mp, you get much less noise. This is the same phenomena that has dark ride pictures looking ugly at a pixel level but looking nice when displayed 800x600 in the forum.

This is only true to a point. I don't think anyone here would have a hard time telling the difference between an 800x600 photo from PotC taken with a 1/2.5" sensor PnS versus a D700. Furthermore, I'm pretty sure that the D700's 800x600 image will be markedly superior, at identical high ISOs, to the same image taken with an A900. (To say nothing of the fact that the A900 maxes out at 6400, just like most modern APS DSLRs. Sure, you could do -2 EC and push it in postprocessing to get 25,600 like on a D700 - but you'd have lost more of the image with such a severe adjustment.)

You know better than that. The big advantage of FF is that it is a larger sensor and can gather more light. It can use that for higher S/N ratios, higher resolutions, less aggressive AA filters, etc. It's not a magical ideal size, it's just bigger than APS-C sized sensors. The IQ advantage of FF over APS-C is roughly similar to the IQ advantage of APS-C over the Olympus 4/3 sized sensors.

...yet at low ISOs, T.O.P. has stated that an APS sensor is actually producing better IQ than a full-frame sensor - and that APS sensor even has more megapixels? On a pure technical level, I am not convinced that FF gains you IQ. The s/n ratios, AA filters, and such, are as much related to pixel density as anything else. Again - the 12mp Nikon FF sensor is the one that seems to have lit everyone on fire. Sony's 24.6mp and Canon's 21mp sensor don't seem to have caused the same levels of excitement.

(On an emotional level, the FF sensor can have advantages thanks to both a slightly different look due to DoF, and a different results with lenses since it uses the whole image instead of just the middle.)

Here's the sweet spot argument again. It seems to be a natural tendency among shooters not contemplating an immediate upgrade to consider their current resolution as ideal. Personally, I'm thrilled with the 21mp sensor resolution on my 5D. When I want a lower resolution, I shoot in sRAW and get a 10mp FF sensor.

As I said, I'd happily buy a 6mp APS-sensor camera with the low-light abilities of the D700. 6mp is still a pretty large resolution especially for those of us whose images stay purely digital 99% of the time with the occasional 4x6 print. Plus, as someone who went from 6mp to 14.6mp, you really didn't see as big of a difference between the lenses on the 6mp sensor, and I think the same is true with a 12mp FF vs a 24.6mp one. A lower mp sensor is not so demanding of having the absolute best glass in front of it.

I guess the real question is: if Pentax released a FF camera tomorrow, would I buy it? If they stuck with a relatively low resolution (say, 16mp or less), they I would be very tempted - but in a large part because I like using so many older film lenses. However, I would also have a hard time justifying the size (especially compared to the smallish K-7) and especially the cost. There's only so much money I can throw at this hobby and I've thrown way too much at it already!

If you want a good comparison of the characteristics of different sensors and cameras, check out the Image Quality Database. You can easily see the correlation between sensor size an IQ there. The top rated sensor is the Phase One P65. Next Nikon full frames (DX3, D3, and D700) with the Dx3 being significantly better. They are followed by the Canon full frames and the Sony full frame. APS-C sensors don't appear until you get down to the Nikon D90. The Olympus 4/3 sensors are still further down the list.

You mean the list that shows the Samsung GX20 in 17th place and the K20D in 23rd place - even though they are, hardware-wise, exactly the same camera with maybe a slightly different jpg processing engine in the software, which obviously wouldn't affect raw files? And they rate the K10D above the K20D? Sorry, color me suspicious of their methodologies. As much as I love science, photography is still too much of an art to be able to be broken down into pure numbers like that. (This is one of the big problems that DPReview has, too, IMHO.)

I'm a little confused on exactly what the difference is between the APS-C and FF sensor - relating to how it does the "zoom". To probably over simplify from what I've read it seems that the APS-C crops the photo that you take, thus giving the appearance of a longer focal length. Since it's often referred to as a crop factor that made sense to me. I.e., 200mm is 200 mm but the APS-C sensor will only use the center portion of the frame. This also gives an advantage to using FF lenses b/c the APS-C sensor is using the sweet spot of the lens. However, in using a FF camera you can achieve the same thing - but just have to do the cropping yourself. And with a FF you will have the advantage of the larger sensor with greater light gathering capabilities - and depending on the camera greater resolution providing finer detail.

Groucho's comment about more reach seems to negate what has been my understanding.

OK - happened to run across this though I wasn't looking. It answered my own question! http://www.digital-slr-guide.com/full-frame-digital-slr.html

You are exactly correct that the APS is just "cropped" - you can theoretically get the same result by cropping a FF image. The point was that the equivalent focal length lens will be smaller or just plain not available on a FF camera. Ie, take a 300mm F4 lens on a crop-sensor camera - that's like a 450mm F4 on a full-frame camera, a lens that will either be non-existent and/or much larger, heavier, and more expensive.

Olympus probably has the best examples of this - since all the 4/3rds lenses are completely new and specifically designed for the small sensor, they have things that you can't get anywhere else - like zooms with constant F2.0 aperture.

 

[MarkBarbieri]

I could take the time to go through and refute your arguments point by point, but I'm going to pass this time. I've provided objected data from one of the (if not the) most respected IQ labs to counter your anecdotal evidence. I have personally experienced the difference because I've shot with multiple different full frame cameras (both Canon and Nikon). If you want to hold the far from mainstream view that bigger sensors quit providing better image quality once they get bigger than what Pentax offers, that's fine with me. Whatever helps you keep the faith. I suspect that the original poster has gotten all the information he needs from either of us.

 

[Groucho]

Well, Mark, I'm sad that you think I'm that simple that I defended APS because of Pentax. I think if you read what I wrote, I put forth several advantages of full-frame (including some that no one else had mentioned yet) and also pointed out some advantages of the 4/3rds sensor (which you'll rarely hear me do. ) As for DxO Labs, the fact that two identical cameras got pretty seriously different scores shows that their system is flawed and results, like all results, must be taken with a grain of salt. Their methodology is skewed to favor sensor size, so naturally large-sensor cameras will do better. Sample variation is obviously not factored in, either. Furthermore, there are too many variables - you cannot reduce the quality of one sensor over another to a simple number.

As for the final comment about "keeping the faith" - one could just as easily say that full-frame owners are coming up with reasons to justify their thousands of dollars of equipment. Jes' saying, y'know. C'mon, let's not go there, we're all friends here.

In the meantime, I'll continue to enjoy my full-frame, manual focus, manual aperture, manual shutter speed film cameras. Not everyone is interested in the same equipment.

 

[Groucho]

I feel like I have to make one final note here. I will not debate the original topic any further but I think some people are getting the wrong idea about what I wrote. Probably the majority of people can skip this message entirely.

1. Nobody here knows what equipment I have and haven't used and I don't know what anyone else has used. It's not fair to judge people based on your assumptions.

2. I swear on the life of my children that the fact that Pentax does not make a FF DSLR has absolutely NOTHING to do with my opinions as stated in this thread. (In fact, were I merely being a fanboy, I would be relaying the opposite opinion, as their long-delayed medium-format DSLR is on a fast track again and hopefully will see the light of day soon.) If you don't believe that, then I'm very sorry but it's the truth. Feel free to ignore anything I write in the future.

3. I confess that I am a little bit insulted and a little bit sad that some people here would jump to the above conclusion. Yes, I (usually) love my Pentax equipment and feel that it's a great system, but I've never claimed that it's perfect or right for everyone. I haven't participated in any "what camera should I buy?" threads for probably well over a year now, and when I did, you could find many examples of me stating that all the DSLRs are pretty much excellent and it was hard to make a wrong choice, and depending on one's needs, a Canon/Nikon/Olympus/Sony system may be a better choice for them. I have never started (and probably would not participate in) a "Pentax PotD thread" - I would also note that despite a good number of Pentax fans and users here, as far as I know, such a thread has never existed. Pentax fans tend to be a bit more inclusive and less hung up on brand wars than users of some other systems. I'd like to think that my record has shown that I try to avoid getting hung up in such silliness, but apparently that impression hasn't always been received.

4. The K20D/D700 link I provided was one I had read long ago, not something I cherry-picked in order to inflame a debate or say "mine's better than yours"; as I stated and the article makes clear, the D700 is much more advanced camera than the K20D, and I would have happily provided the link if it said was talking about the 40D or A700 instead of the K20D. T.O.P. is usually a very interesting blog and one I recommend checking out; it is also generally very brand-agnostic and is a favorite of some well-known folks in the photo field. The author (Mike Johnston) is a real photographer, and the site is about real photography more than raw measurements like you'll find on DPReview. In other words, it's not pushing any agendas.

5. I don't feel that I was arguing with anybody (and only one person responded to my response with a contrary opinion, anyway.) As I said, I'd like to think that we're all friends here, especially us regulars. I'd like to think that we can have a healthy disagreement or constructive debate without it turning into a "you vs me" thing. Besides, I even wrote in my initial reply that I was not putting in an opposing viewpoint, just that I wasn't ready to go as far as some earlier posters had.

OK, I'm done. Thanks for reading.

 

[Gdad]

Yummier, now that's technical term I can understand......

Yep Dave- It IS way Yummier.

I think we all need a

 

[Evad]

Yep Dave- It IS way Yummier.

I think we all need a

Almost makes me feel sorry for asking the question.....

And yes I agree 100% a is needed!!