Luminous Landscape Forum
Equipment & Techniques => Digital Cameras & Shooting Techniques => Topic started by: Paulo Bizarro on October 25, 2004, 03:27:53 am
-
A never-ending discussion topic. Personally, it is only cost that prevents me from getting a full-frame DSLR from the EOS line. With a smaller sensor camera, my 24 TS lens would become useless, and my 135 f/2 would become useless.
I wonder how much a Digi Rebel fitted with a full-frame sensor would cost? I don't need full-frame sensors in shooting machines like the 1 series, but I would welcome full-frame sensors in lower tier cameras. Even then, perhaps they would remain too expensive...
In the meantime, I am quite happy with Velvia 100F.
-
Here is my opinion on this.
With a given manufacturing technology, it always cost more to produce 35mm size sensor versus APS size sensor. It always was in the past, it is now, and it always will be. Even if the semiconductor process yield reaches 100%, the 35mm size sensor will cost 2X more (just from area alone). This feat (100% yield) is rarely reached by even best manufacturers. Typically, 35mm size sensor will cost any where between 3X to 9X more than APS size sensor (this estimation can be derived from a given probability of defect density).
So, given the higher cost of manufacturing the 35mm size sensor, which Camera makers would ever put the 35mm size sensor into their entry line? It simply will not happen. So, I see that consumers willl always get the APS size sensor on their Camera, while the 35mm size sensor will strictly be reserved to Pro-line camera ($3000 and up).
-
Whew!!! This has gotten way over my head. I've noted in the countless past instances when there's been pages of very technical/mathematical discussions to try to prove some point or another, no consensus was ever reached. Everybody keeps believing whatever they believed to start with and they're sure that their math, etc. proves it. I'd rather just have camera/lens combinations to test by shooting my test grid array and decide what's what by looking at the results. "Probieren, probieren geht ueber studieren" is what my German engineer daddy often said. It means (more or less) "experimentation rules over theorizing".
If a compact and light weight (small or large sensor) camera as good as my 1ds comes along at a tempting price I'll buy it, but not based on any theoretical discussions related to the technology involved. I'm a dummy, ya gotta show me.
-
This important COST factor will always drawn line between professional market and consumer market.
I can't imagine anyone seriously contesting this. The issue initially was about quality issues, and reducing costs is not the same thing as increasing quality.
As for the idea that small sensor cameras will be rivaling large sensor, this is surely a bit speculative. Tomorrow's small sensor cameras may rival today's large sensor, but not tomorrow's large sensor. Canon is obviously committed to sustaining the growth of large sensor cameras. Of course the highest quality will always be most expensive and mainly for the pro market. That's always been true for film and can't help but always be true for digital.
-
I mean by this that full frame and MF backs will remain a Pros-wealthy amateurs thing and I dont see the prices dropping considerably in the near future. It still amazes me the amount of pros that worked with 35 mm film cameras and produced very good results( probably moved by their adventorous back-packing/helicopter-hanging/mountain climbing needs). Look Jean Arthus-Bertrand´s world from the air shot nearly exclusively in canon 35mm. APS sized sensors are capable of an amazing quality right now and will probably improve considerably in the next couple years, allowing a lot of proffesionals to work with them proficiently. I agree that larger sensors will ALLWAYS give better image quality, but I have the feeling it is going to be much more interesting/profitable for the big companies to concentrate in getting the best out of smaller sensors. APS size will (does)allow enough quality for making it questionable the extra cost for FF for many pros allready. I think the landscape of the Photography market will change considerably in the years to come and APS size will be strengthened and maybe even favoured...
Again, what can you buy with 2cents???
-
The articles on "Luminous Landscape" regarding full frame sensors are fascinating. As someone who switched from a Nikon D1x to a Canon 1DS I guess I'm in the full frame camp.
But I'm puzzled by one of the rebuttal points.
Michael, you said there's no quality advantage with a smaller sensor. I'd agree with respect to the sensor itself, however I'd have thought that a smaller sensor enables a lens with a smaller image circle, and wouldn't this promote better image quality?
I've recently been looking at the performance of the new generation of "digital" large format lenses designed to cover the 645 and 6x9 formats, they're certainly delivering a useful quality advantage over my modern 4x5 lenses by virtue of more restricted image circles. And at the other end of the scale I recall one of the key justifications for Minox sub-miniature cameras was that their tiny lenses were setting new performance highs, the Minox problem of course was that a wide range of film stocks to take advantage of this performance was never really available!
Incidentally Michael. you mentioned recently that you had trialled the P25 and would shortly publish a practical review. Any idea when it will appear? I'm expecting to take delivery of a P25 sometime in November. As I could only try out the H25 before placing an order I'm eager to get some second opinions from outside a studio!
-
I think Michael's rebuttal is primarily focused on image quality, which is probably his primary consideration. I think there are other considerations though.
It is going to be a question of volume and economies of scale. Not everyone needs the image quality that a full frame sensor will provide, and not everyone will be willing to pay a premium for it. There always will be a premium, even if the gap is getting smaller. The computing power, and memory card sizes to deal with higher pixel counts add to the premium, something a lot of people don't account for when they are looking at higher resolution cameras.
If image quality were the only consideration, then 35 mm would not be so popular.
-
Personally, it is only cost that prevents me from getting a full-frame DSLR from the EOS line.
A candid admission. I think a lot of the folks that claim there are other reasons not to get a full frame DSLR are sour graping and twisting logic to the breaking point.
Since almost all my shooting is on strenuous backpacking trips, I hope someday that hi res full frame sensors will be available for something much lighter than what's available now. I still hope (with waning expectations) that some day there will be really good ultrawide zooms. In the meantime I'll continue to be happy carrying my 1ds and 5 prime lenses on my backpacking trips; well, sort of happy. My back and my old climbing injuries are not always so happy with this abuse. Now something like a Digital Rebel and the new Canon 17-85mm IS lens, but with full frame sensor and optical quality to match; I'd probably sell my soul for that. My gear weight for the most extreme backpacking trips could be reduced to 10% of what it is now.
-
Having more carefully read the whole "two Michaels" debate, I have a couple of comments.
There seems to be no disagreement that larger formats like 645 will be the choice for some niche of high end digital photography, just as larger than 35mm film format cameras survive now, albeit greatly outnumbered by 35mm film SLRs even in professional usage.
MJ seems to be addressing where the SLR mainstream will settle (forget the overall mainstream, which is solidly settled somewhere below 2/3" format, and maybe heading towards the camera phone.)
I agree with MJ that lenses will likely be the persistent "cost and convenience" factor causing smaller format DSLRs from 4/3 through EF-S up to DX to be far more numerous than digital cameras in 35mm format and up.
However, as I have said before, the fairest comparison is at equal effective aperture diameter, not equal aperture ratio: 200/2 for DX vs 300/2.8 for 35mm, 300/2.8 vs 400/4, 400/2.8 vs 600/4.
Such comparison gives equal DOF wide open, and about equal speed for a given noise level once the speed/noise advantage of a larger sensor is accounted for. The price, weight and size comparisons still seem to favor the smaller format with these shorter but "brighter" lenses, but not as nearly as much as if one compares at equal maximum aperture ratios.
Matching lenses this way does elimimate at least a number of common arguments, including one that MR repeats, based on the lower noise of larger sensors at equal ISO speed settings. For example, if when going from 35mm to true APS-C format (a factor of 1.4x) you choose lenses with focal length and maximum aperture ratio both reduced by that factor of 1.4x, the APS-C lens gives
- about the same or lower price and weight
- the same DOF wide open, and in general the same DOF at one stop faster
- twice the exposure level at the same shutter speed and DOF (or same shuter speed and wide open), allowing you to use half the ISO speed setting unles you ar already at minimum. This at least potentially balances the higher noise levels seen if you compare at equal ISO speeds.
In more detail, with the same pixel count in both sensors and hence pixels of half the area in APS-C, this doubling of "lens speed" balances the halving of pixel area and hence gives the same amount of light gathered at each pixel. This seems likely to give similar noise levels.
The main potential disadvantage for the smaller sensor is blown highlights. Not a problem when using elevated ISO settings (underexposing the sensor and then amplifying more), but it gives larger sensors a possible advantage in dynamic range in situations where the minimum ISO setting can be used.
A final disagreement with MR; only a few new lenses are needed when changing to an APS-C format DSLR. It should be clear by now that there is no need for Nikon, Pentax, Konica-Minolta etc. to introduce entire new lens lines for smaller DSLR formats, or for lens owners to replace their whole 35mm format lens collections.
The only new lenses needed are those reaching wide angle focal lengths (below about 50mm). Nikon has already produced most of the DX lenses they need; most photographers only need to add one or two lenses to their existing collection, maybe trading away one or two 35mm "wides". Specifically, the majority of current Nikon 35mm film SLR users probably only need to add the 18-70 f/3.5-4.5 DX when changing to a Nikon DSLR.
-
So, given the higher cost of manufacturing the 35mm size sensor, which Camera makers would ever put the 35mm size sensor into their entry line? It simply will not happen. So, I see that consumers willl always get the APS size sensor on their Camera, while the 35mm size sensor will strictly be reserved to Pro-line camera ($3000 and up).
This is the point to me. A larger sensor will mean better image quality, but will it be worth the premium in price. Especially considering the needs of the average consumer.
I don't think this site is neccesarily a good sample space when it comes to the needs of the average consumer. I consider myself a fairly involved amature, and I would have a very difficult time justifying (rationalizing would probably be more accurate) the purchase of a $3k full frame camera (if one existed).
The question is whether or not the cost differential is small enough to be justified by improvements in image quality that most people will not even be able to see.
-
> As soon as a proportionately lower aperture ratio is available on the shorter focal length lens used with the smaller format, you can get the same DOF as in the larger format, but with a "faster" f-stop
That is where the aberration problem creeps in.
Agreed: the lower limit on usable aperture ratios sets an upper limit on performance in a given format, and that limit seems to be about f/1.4. I even note a trend towards a f/2 limit. Aperture ratio is similarly limited by sensor characteristics; beyond f/1.4, light reaches the sensor in a very broad cone, and light from near the edges of that cone comes in at such an off-perpendicular angle that the sensor cannot detect it well.
So, for people who still want extremely large apertures, for extremely shallow DOF or extemely high shutter speeds, even with the far higher ISO sensor speeds possible with digital cameras compared to film, larger formats will continue to be attractive. But this is unlikely to influence the DSLR mainstream; look at the relatively small apertures being offered on all recent DSLR oriented lenses like the Canon EF-S, Nikon DX and Pentax DA models. The Nikon 200/2 and Olympus 50/2 and 150/2 and the 7-50 f/2-2.8 lens of the Sony 828 are the "fastest" recent lenses, and they are still only f/2.
-
Didger,
actually there seems to be no disagreement about the facts, just a question of which facts one considers more relevant.
No-one seems to disagree with the claim that, if you use sensors of the same pixel count, camera at the same distance from the subject, lens giving the same angular field of view, and the same shutter speed, but the sensors are of different sizes (so that the focal lengths are different),
a) if you use the same exposure index ("ISO setting") with each sensor, and hence the same aperture ratio, the larger sensor will have less noise (due to the greater light gathering power of the larger pixels) and less depth of field (due to the longer focal length)
if you choose the apertures in each case to get the same depth of field, the larger format will need to use a higher exposure index, so the noise level comparison becomes far less clear.
Rough theory suggests that noise levels will be about equal, but as you say, it is better to do experiments at this stage.
To me, shutter speed and depth of field are direct characteristics of the image, whereas exposure index is not, so comparison ( seems of far more practical relevance.
Note well: I am not claiming any advantage in this repect for smaller sensors, just arguing that a claimed advantage for larger sensors is of little practical significance. In that sense, I agree with Michael; the main advantage of smaller formats is cost and convenience, while larger formats have some advantages, like more resolution at a given dynamic range.
Frankly, I think this is yet another of those hangups where people are used to comparisons of different options when working with the same format, and do not take account of all the things that change when trying to make a relevant comparison between different formats. Most of these issues come down to comparing at equal aperture ratio even though image properties are very different at equal aperture ratio in different formats.
-
I have new evidence to prove my case.
Please check this out.
http://forums.dpreview.com/forums....0854751 (http://forums.dpreview.com/forums/read.asp?forum=1021&message=10854751)
-
MF digital as represented by FF and above sensors will grow to the same size as the old MF film market. Digital backs will dissapear in favour of fully integrated cameras which will either take lenses for 35mm (1Ds MKII, DCS Pro N/C etc) or MF (Mamiya ZD, Hasselblad HD).
4/3rds and APS-C sensor cameras will take over from the quality 35mm film market and this is where the bulk of sales will be for the foreseeable future. Just like it used to be for 35mm, these cameras represent the ideal compromise between image quality and camera size and weight. Compatibility with existing lens technology is a bonus.
-
I believe whe are going to have APS size for quite a while.
Yes, no one is arguing this. We've had 35mm film, MF film, and large format for quite a while too. It's not a question of APS vs full frame 35mm. They can and will co-exist in exactly the same way that 35mm and MF have co-existed, with similar price and customer base profiles.
-
We've had 35mm film, MF film, and large format for quite a while too. It's not a question of APS vs full frame 35mm. They can and will co-exist in exactly the same way that 35mm and MF have co-existed, with similar price and customer base profiles.
Just been lurking on this topic, and I believe that your statement here sums it up. The discussions about "quality" are rather moot, since "quality" is a highly relative term, dependent on the style of photography you do. A landscape photographer may value pixel-count and accuracy
to capture the integrity of the scene. A street photographer may value speed and stealth. (I met a very cool photog who uses the camera in his cell phone to make some amazing images... yes, blown up to 20x24). A fine art photographer can fit anywhere along the spectrum. To make the claim that one camera is inherently "better" incorrectly assumes that all photographers value exactly the same kind of tool.
Personally, I hope both full-frame and small-frame continue to exist alongside each other.
-
There's nothing inherent in a smaller image circle that produces higher image quality. The trade off is, of course, the need for greater magnification.
I ordered a P25 in Contax mount last week. It should be here within about 2-3 weeks. I'll have a full field report not long after it arrives.
Michael
-
If image quality were the only consideration, then 35 mm would not be so popular.
Well, cheap point and shoot cameras are even more popular than 35mm and most popular of all are disposable 35mm cameras like you can buy in convenience stores. So what? I think it's fairly safe to assume that on a landscape forum with a lot of very serious amateurs as well as semi-pro and full on pro members, it's fairly safe to assume that almost all of us want the best image quality we can possible afford. I know I do. Image quality is THE consideration. Economic factors are hurdles to overcome in the eternal quest for improving image quality.
-
I can just one rather indirect way that a smaller sensor can allow better image quality, and that is when we are faced by by price and weight limits on the kit we can own or carry.
Downsizing the focal lengths and image circle to get the same field of view with a smaller format might allow increased resoluton in the sense of line pairs per millimeter, but no more than in proportion to image size, so I see no likely gain in "line pairs per image height", which is what counts for print resolution.
However, that smaller format lens can need less of the rather expensive optical glass to make it, reducing the price and weight. For example, the new Nikon 200mm f/2 seems intended to do with DX format what a 300mm f/2.8 does in 35mm format, but is set to be less expensive, even
with its extra stop.
That gives us budget limited users of smaller formats the chance to put those savings into higher quality lenses, faster lenses, or more lenses, possibly improving the quality of some of our images.
Also, when weight is limited, the smaller format can allow carrying more lenses, or lenses of lower minimum aperture ratios (like 150/2 in 4/3 or 200/2 in DX vs 300/2.8 in 35mm), again possibly improving some images.
For example, Michael explained his choice of a 500/4 over a 600/4 in terms of weight: in an "APS" format, something like a 400/4 becomes an even lighter option, with "600mm equiv. FOV".
-
> However, as I have said before, the fairest comparison is at equal effective aperture diameter, not equal aperture ratio: 200/2 for DX vs 300/2.8 for 35mm, 300/2.8 vs 400/4, 400/2.8 vs 600/4.
Great point! Might not matter for rocks and trees, but if you use selective DOF, it makes a huge difference.
The convergence of aberrations and diffraction as the sensor gets smaller is also an issue, but not yet critical at APS size.
-
All else being equal, higher levels of sensor noise and less dynamic range with the smaller sensor. You have to shoot at lower ISO even though you can use a larger aperture, so you don't end up ahead in the long run.
-
But... a compact G5ish digicam with an APS sized sensor? now that would be tempting
Already waiting in line for one of those
-
so how do you justify your claim that smaller format and pixels have "higher levels of sensor noise"?
That would be based on the pretty much universally observed phenomenon that larger format sensors have lower ISO noise than smaller ones. Digicams are pretty much useless noise-wise above ISO 400, DSLRs can yield acceptable results up to ISO 1600. It's fairly easy to demonstrate this, just go to your local photo store, shoot some test shots with a variety of cameras, and correlate observed noise levels with the pixel size on the sensor.
-
Michael, allow me the indulgence of posting an article I had prepared for another forum.
1. You already have a lens system which is optimized for 35mm. Every glass in your range (except (except for newly introduced glass, like the EF-S and DX) delivers an image circle for a 35mm frame. I would argue that EF-S and DX is a kludge, definition of a kludge being "an error introduced to fix another error". If Hasselblad wanted to produce a digital back for its MF camera, would it buy a 6.0MP APS sized sensor from Sony? The answer is "no" for many reasons, but one of the prime reasons is because too much of the imaging circle has been wasted. The argument remains true, in a smaller scale, for FF vs. APS sized sensors.
2. Expanding on my first point, the greatest expense in designing a lens is to ensure the lens performs consistently from corner to corner at wide apertures. This is one of the touted advantages of DX/EF-S/Four-thirds lenses. Paying a small fortune for a 600 F/4 and then throwing away the most expensive part of the image sounds wasteful to me. This would not be so bad if the manufacturer rationalised the entire lens range so that savings could be realized across all the lenses - something that the 4/3 consortium is trying to achieve, something Nikon is halfheartedly doing, and something that Canon will not do.
3. To continue along this line, where are the savings which reduced crop lenses have promised us? First 3 examples, price obtained from B&H, last example, Canon Australia website:
Nikon 10.5mm DX fisheye, USD599.95 - Nikon 16mm fisheye (full frame) USD$564.95
Nikon 17-55/2.8 DX, USD$1349.95 - Nikon 28-70/2.8 (full frame) USD$1329.95
Canon EF-S 10-22/3.5-4.5 USD$599 - Canon 17-40/4L (full frame) USD$674.95 (not strictly comparable, since the 17-40/4L is a constant aperture lens)
Canon EF-S 17-85/4.5-5.6 IS AUD$1099.00 - Canon 28-135/3.5-5.6 IS AUD$999
... I am sure you will agree there is no difference. We are still paying the same price for reduced crop lenses as we were for full frame lenses.
4. The next part of my argument concerns sensor design. Among other things, sensor designers are concerned about resolution, dynamic range, and noise suppression. Pixel pitch (the size of each individual photo pixel sensor, in micrometers) is just one out of many factors which influence these. People like to use the rainwater and bucket analogy which is a good one - a larger bucket allows more precise measurement of rainfall. A small bucket spills water too quickly. If there is very little rainfall, the small bucket may not gather any rainwater at all.
You can design a more efficient water gathering system (microlenses), you can design a better ruler (both tricks employed in the new 20D and 1DMk2) ... but in the end bigger buckets are still better.
A full frame sensor ultimately allows you to fit more, and larger pixels. Eventually you will hit a limit on a smaller sensor before the conflicting demands of resolution and larger sensors force you to look at other means of increasing dynamic range and reducing noise. You just hit the limit later on a FF sensor. If two manufacturers have exactly the same noise reduction and image processing technology, the manufacturer that can produce a larger sensor will have higher resolution, increased dynamic range, and less noise.
5. Viewfinders. Its not strictly necessary to have a larger viewfinder - it's just nice to have.
-
Only people who would buy $8000 Camera would be either professionals or serious/affuluent amateurs which accounts for no more than 10% of total DSLR revenue.
So what? What percentage of total film camera revenue is for 8x10? This format has been around since the very invention of photography and may stay around the longest of any film format, since it will be the last to be made obsolete by digital.
The 35mm film size sensor Camera will only get more rare and hard to find.
The Canon marketing folks don't seem to feel that way and their #1 position makes me trust their judgement more than yours. I run into countless photographers on my excursions and very few are 4x5 shooters and I've only actually once seen an 8x10 in the field. However, these large format cameras are NOT hard to find. Try a Google search.
Here's my prediction: 35mm film size sensor cameras will only get more popular and easier to find and also gradually somewhat cheaper. Another player entering the arena could drive prices down more and a major technological breakthrough (which no one can predict) could drive prices down a lot. Even now a lot more people are getting into large sensor because of all the used 1ds's for sale now so much cheaper.
I'm neither affluent (you should see my house and my car) nor very much pro so far, but I have a 1ds and I vacillate about hustling to get the money together for a 1dsMKII. It's more a matter of priorities than affluence. Countless ordinary folks have cars worth $30,000+ and houses worth $100,000+. That's their priorities. 1ds owners tend mostly to be pretty fanatically enthused about this camera and format and this can't help but promote growth. I "converted" a fellow Sierra backpacking photographer (Eos film camera) to 1ds and Zeiss lenses without even trying and this guy is also neither pro nor affluent; just another quality fanatic. Stay tuned and watch your convictions erode and stand by to watch the growth of MF digital. Horseless carriages were a passing fad too.
-
I believe that the simple fact that Canon an Nikon have started investing big bucks in the manufacture of "digital-lenses" of the likes of the EF-S ones is a clear signal of what is going to happen in the near future.
I believe whe are going to have APS size for quite a while. It suites very well the needs and conveneinces of the majority of the potencial future buyers, and we musnt forget that Canon is in this for the money and not for their love for art...
Just the opinion of a poor mortal camera buyer... :cool:
-
You addressed your question to Michael, but I'm not shy, so I'll go for it also. Yes, a smaller image circle lens can theoretically be better within that image circle than an otherwise comparable lens that covers a bigger circle. HOWEVER, the problem is that wide angle lenses are not as wide with a small sensor, so if you want a small sensor camera to be ultrawide then you're faced with the problem of making a sharp lens that's around 10-12mm focal length. Even for small image circle that wouldn't be easy. What you gain with a bit of extra resolution and a relatively bigger "sweet spot" in a small image circle lens, you lose with the fact that the total final image area is also smaller and therefore effectively less enlargable than a large sensor image. The issue is which format will give you the biggest sharp enlargement and not which format has the sharpest lenses. MF lenses are not as sharp as 35mm, but MF nevertheless give you sharper big prints. Same thing applies to the difference between large and small sensor 35mm DSLR's.
Maybe Michael has a different take on this and can provide a clearer answer.
-
Please, someone correct me if I'm am wrong here or oversimplifying, but it is my understanding that the main advantage of using a smaller area of a lens is to avoid the outer area that may show more distortions. However, there are some lenses that are relatively distortion-free across the entire image circle and if you are using one of these lenses with a smaller sensor you would not be getting the greatest results from the lens. Lenses have a quality and sharpness factor similar to that of sensors where the bigger you are able to go the better the overall image quality. Of course the other factor that many people consider as an advantage with smaller sensors is the bigger magnification factor which is not an advantage for everyone.
T
-
Michael made the point about APS sensored cameras not having a size advantage against FF. When APS film slrs were made by Canon and Minolta they were more compact. I think that size may have more to do with perceived value to the buyer who wants their new toy to look like £1500 of metal. I am sure that there is a place in the firmament for a range of DSLRs which take advantage of the smaller and lighter body and lenses that a reduced image circle optical geometry allows. It will take time to get there as manufacturers trim 3mm off the body size year on year to give us an excuse to upgrade.
But... a compact G5ish digicam with an APS sized sensor? now that would be tempting.
Tony Collins; 10D but sitting out this years upgrade. 30D anyone?
-
I don't think anyone would contest the economic and weight benefits of smaller sensor cameras and smaller image circle lenses. When I think of what carrying about 17 lbs. of photo gear on long backpacking trips does in terms of risk to my back and pain to my old climbing injuries, I think about how much nicer a Digital Rebel and 17-85mm IS lens would be. Total weight about 1.5 lbs. and no need for a tripod and I'm sure a Digital Rebel is more economical for battery weight and use too. However, I won't switch to a smaller camera and lenses unless the quality gets at least as good as a 1ds. The Nikon DX2 (or whatever exactly it's called) has more Mpixels than a 1ds, but I'm so doubtful about the sensor quality (esp. noise) and the quality of those special zoom lenses (especially ultrawide) that I'm not even very seriously inclined to check this camera out. I'm also a bit put off that a $5000 camera would have such a mickey mouse consumer feature as in camera multiple exposures. My hopes that Nikon would end up a serious contender in the high end pro DSLR field have pretty much evaporated. I think there's a much better chance that I'll end up getting a 1ds MKII than getting any sort of small light DSLR any time soon. Too bad for my back, but better for my images.
-
Smaller sensors mean smaller focal lengths for the same FOV, and therefore a larger DOF.
Only if you assume the same aperture ratio, but why do that? The long time trend in cameras is that lower minimum aperture ratios are available and usable for shorter focal lengths and smaller formats, and this lives on today with things like f/2-2.4 zoom lenses on some 2/3" format digital cameras.
As soon as a proportionately lower aperture ratio is available on the shorter focal length lens used with the smaller format, you can get the same DOF as in the larger format, but with a "faster" f-stop, so that it is possible to use a higher shutter speed, or a lower ISO setting to reduce noise levels. What is the downside to the smaller format then?
-
> As soon as a proportionately lower aperture ratio is available on the shorter focal length lens used with the smaller format, you can get the same DOF as in the larger format, but with a "faster" f-stop
That is where the aberration problem creeps in. As the aperture gets larger relative to the focal length, it gets harder to make the lens. Look at the ultra wide problem even on 35mm and the great quality from the F1 normal lenses - even the Canon and Leica F1s are terrible compared to the cheapest F1.8s. I would need a 28 F1.0 on my 10D to match my 50 1.4 on a film camera. How about a 20 F 1.4 to match my 35 F2? Probably the only good lens match is the 35 F1.4 on an APS camera - but it is a big and expensive lens. Things are easier at the long end, but then they always are because you do not have bend the light as much.
-
so how do you justify your claim that smaller format and pixels have "higher levels of sensor noise"?
That would be based on the pretty much universally observed phenomenon that larger format sensors have lower ISO noise than smaller ones. Digicams are pretty much useless noise-wise above ISO 400 ...
One more time: smaller formats can generally use lower ISO settings, so comparisons at equal ISO are "correct" but almost completely irrelevant. More so since the original topic raised by Mike Johnson is APS vs 35mm formats, not digicam vs DSLR.
That would be based on the pretty much universally observed phenomenon that larger formats generally must be used with higher, slower aperture ratios, due to either depth of field requirements or the practical limits set by cost and weight. Neither Hasslebland nor Rollei offer anything faster than f/2 in medium format.
It would be perhaps accurate but very misleading for me to say that larger formats are slower, because of the larger aperture ratios that they often need to use. I would be telling only one half of the story, you are telling only the other half.
What is true is that at the same ISO, shutter speed and pixel count, a larger format has lower noise levels, but also less DOF.
Surely, in a landscape oriented forum we can acknowledge that depth of field is very often a limiting factor in choice of aperture. Then, as I have explained already, either the larger format must use a higher ISO than the smaller, enough higher to cancel its noise advantage, or the smaller format can use its optimum (minimum?) ISO, in which case noise is not a significant issue. At least not for any DSLR that I know of, and not even for the tiny 2.7 micron pixels of the Sony 8MP 2/3" format sensor according to Michael.
Once DOF is relevant, the worse performance at ISO 400 of digicams compared to DSLR's is irrelevant.
-
I agree with your argument about full frame sensor. However, you are over-looking one important point.
The COST FACTOR.
Currently, the cost of produing full frame chip is prohibitively expensive. And, this will not get any better in short run (please refer to my earlier posting), definitely not in next several years.
This important COST factor will always drawn line between professional market and consumer market.
-
Larger sensor manufactured with same technology will have advantage over smaller sensor in terms of signal to noise ratio. However, I am not so convinced that pixel in full frame sensor will have significantly better result than pixel in APS size sensor given advanced in-camera image processing and on-chip noise reduction process. Let's take 1D MKII versus 20D for an example. Most people would be hard pressed to see any difference in noise performance between two camera upto ISO 1600.
I predict that performance gap between full frame sensor and APS size sensor will get harder to detect at average viewing distance. It will still be there, it will get obvious only in extreme cases such as sever under-exposure or ISO rating of1600 or greater.
Furthermore, performance of typical 35mm SLR lens declines along the periphery. Thus, by using the APS sensor, we get to use the sweet spot of a given lens.
As for the 35mm film size sensor, Canon may support them in a $8000.00 Camera, but how many people would buy the $8000.00 Camera? If they ever produce the full frame Camera under $3000, I will be the first to buy it. I am predicting that such will never happen within next several years.
Only people who would buy $8000 Camera would be either professionals or serious/affuluent amateurs which accounts for no more than 10% of total DSLR revenue.
I am predicting that, over next five years, market will get dominated with APS sensor size DSLR. With Minolta, and Pentax jumping in, this category of DSLR will only get better, price will go down, and ultimately, consumer will be the winner. The 35mm film size sensor Camera will only get more rare and hard to find.
-
Didger, you see we can agree. I have already contacted CNN, but I was rejected by Al-Jazeera, because I foretold the demise of Bin Laden in Tora Bora. Sadly, he would appear to still be with us. Alas...
The last bit of your message is a human aspiration we can all relate to.
-
Ooops, Michael's reply and mine "crossed in the mail" and he got there a little sooner. His reply is substantially the same as mine, only briefer.
-
Great point! Might not matter for rocks and trees, but if you use selective DOF, it makes a huge difference.
The convergence of aberrations and diffraction as the sensor gets smaller is also an issue, but not yet critical at APS size.
And this is the point I think both Michael and Mike haven't addressed ...
Smaller sensors mean smaller focal lengths for the same FOV, and therefore a larger DOF.
Some feel that's a virtue of the digicams and their small sensors: the tremdous FOV. You don't have to worry about focus accuracy as much. In fact, I see a lot of posts by new comers to DSLR's complaining that their cheaper digicam took sharper pictures, not realizing they were seeing the large DOF of the digicam, not a sharper picture.
I see it as a disadvantage. I like being able to control the DOF. It seems to me that the traditional 35 mm size is just right for being able to have a nice small DOF wide open and still get a reasonable one when stopped down. Search for posts from novices having learned about their craft and are trying to get background blurr from the digicam. Lord knows I tried with my G3 at f/2 and didn't get much.
Sure, someday they'll put a 8MP sensor the size of a pin head in a cell phone and you'll get a clean image with no noise. Just don't go looking for any bokeh.
-
All else being equal, higher levels of sensor noise and less dynamic range with the smaller sensor. You have to shoot at lower ISO even though you can use a larger aperture, so you don't end up ahead in the long run.
But nor are you worse off, so how do you justify your claim that smaller format and pixels have "higher levels of sensor noise"?
The physics is this, for the example of doubling linear size.
To get the same field of view, depth of field and pixel count, doubling linear pixel and sensor size requires doubling focal length and doubling aperture ratio, which means pixels have four times the area and 1/4 the intensity of illumination, so the same total rate of illumination per pixel. For the same shutter speed, each pixel receives the same amount of light: same signal. As to noise: photon shot noise will be the same, dark current noise in larger pixels will be somewhat greater (more total length of well edges, along which the thermal electron diffusion happens, which is what causes dark current noise). Amplifier noise can be expected to be the same or slightly higher with the larger components needed to handle the larger maximum output of a larger pixel.
So in this situation, smaller pixels give the same signal and the same or lower noise levels, so the same or better S/N ratio.
I agree that with current technologies, bigger pixels have higher dynamic range, manifested as more highlight headroom due to larger electron well capacities.
However, this is only relevant when there is enough light that the sensor can be used at minimum ISO or close to it. At higher ISO, the "underexposure" mostly eliminates the risk of blown highlights even with smaller pixels.
-
Hey, call the news services. I find myself in total agreement with a Drew message. I don't see how things could possibly fail to go just that way.
I don't care what the bulk of sales are now or will be in the future or about ideal compromises, but I care a great deal about high end digital 35mm becoming as common (and well supported with lenses) as high end 35mm film used to be and I'm looking forward to digital MF becoming as common as film MF. Film MF has never been cheap, but also not exhorbitant like digital MF so far.
I just hope it all comes together while I still have the health and fitness to get out so much.
-
and I hope youll excuse my english..(its a bit rusty...) :cool: