Full frame or cropped?

Full frame or cropped?

The arguments of the last few years concerning Film versus Digital look likely to be replaced with a new, and probably just as contentious battle, that of full frame versus cropped sensors.

With the two big players in the dSLR production game stating that they intend to go in different directions, Canon producing more full frame cameras and Nikon not planning full frame in the short or medium term, and a third, dark horse coming up on the rails in the form of Sony, which format is of the most use to us, the folks in the street.

Well, most people who come up with quick answers would say it depends on the type of pictures you take. Those with a penchant for landscapes will want full frame cameras which support wide angle lenses whereas those preferring sports or wildlife photography will happily opt for the cropped sensors that give that extra length to their telephoto lenses.

But is it that simple?

Well no, because aficionados will then claim that full frame sensors can be cropped to achieve the same benefits as using a cropped sensor and those on the other side of the fence will gleefully point out that their cropped sensor has the same number of pixels as the full frame competitor and that the full frame will loose resolution by cropping, making the cropped sensor a better bet.

This argument will then continue round in circles, including pixel size and density, S/N ratios of bigger/smaller pixels, softness and vignetting at the edges and so on, ad infinitum.

So where is the truth, is one format ‘better’ or is the answer somewhere in the middle ground.

As is so often the case in these types of arguments, there is no definitive answer, and for that reason alone, the fact that different manufacturers are taking different paths is good news for us consumers because it gives us the choice.

As the playing field stands at present, and leaving out medium format purely on the grounds of cost, we can have up to 12mp on a cropped sensor or 16mp on a full frame sensor. Although cropped sensors are available in crops of 2x, 1.7x, 1.6x, 1.5x and 1.3x, for the benefit of this article and argument, we will stick to the 1.5x as the 1.7x and 2x are rarer, the 1.3x likely to go in favour of full frame once processing speeds are fast enough and the 1.6x is a tad harder in terms of the mathematics!

We all know, because the manufacturers keep telling us so, that more mega pixels are better, and we have gone from 4mp in top end cameras a few short years ago to the present incumbent at 16.1mp. (Canon 1DsMkII) However, if we take the above argument about cropping full frame sensors and do a 1.5x crop on a frame from the 16.1mp camera we are left with 10.7mp, whereas the top end 1.5x crop camera has 12.2mp  (Nikon D2X). And we can probably take it as read that lesser cameras will reach these number in the not too distant future, as the recently announced Canon 5D has proved by out-pixelling the earlier 1Ds! There are also a raft of 10mp cropped sensors now hitting the shelves.

These figures are getting into the realms of serious resolution, and the next concern becomes the lenses that are put on the front of these megapixel marvels. Now this is where the argument becomes a little more interesting, due mainly to the efforts by both the system manufacturers as well as the independent lens manufacturers like Sigma to overcome the main shortcoming of the cropped sensors, that of the loss of wide angle capability. Whereas anything below 24mm was considered to be ultra-wide angle on a 35mm full frame system, cropped sensors need to be going below 16mm to achieve the same coverage.

With the cropped sensor dSLR’s becoming so popular, these manufacturers have designed lenses down to 10mm in focal length, overcoming at a stroke the ultra-wide angle advantage of full frame. And because these lenses are all, without exception, new designs, the makers have put all the modern design techniques at their disposal into them. And that includes all the experience accrued in making short focal length lenses for the multitude of digicams with comparatively tiny sensor sizes.

The results, backed up by real SFR/MTF data, prove that these new designs outperform their older cousins by some considerable margins. The bad news is that they don’t work on full frame cameras or will vignette badly if they do.

With some commentators claiming that the present 16+mp full frame cameras are already out-resolving even the best of lenses it would follow that the same can be said of the 12+mp cropped cameras.  However, these newly designed lenses take into account this need for improved resolution and are made with this requirement in mind. There are, of course, other difficulties in making such ultra-wide lenses, such as controlling the chromatic aberrations that are the bane of the digital photographer and distortions that such wide angles need to overcome, but with the aid of modern CAD (Computer Aided Design) systems and new coatings as well as improvements in the manufacturing processes of moulded elements these problems are largely being beaten.But because these lenses are being made exclusively for the cropped sensor cameras, their wider field of view is not transferable to the full frame systems. With some makes, this is purely because of vignetting, but with others, most notably the Canon EF-S models, they will not work physically due to their construction and are likely to damage the camera if tried!

So where does this leave the man in the street? Well, as is often the case, the next consideration will be cost. We have all learnt that, as with all electronics, the price will come down as the technology advances, and this is most certainly the case with digital imaging. The cost of producing full frame sensors has come down enough for Canon to feel it is worthwhile to produce the full frame 5D, and they expect it to come down further, but it follows that the cost per unit of cropped sensors will come down by a similar margin, negating any advantage there.

The new lenses do not need to produce such a large image circle, and consequently do not need as much of the expensive grades of glass in their construction. Although the cost of materials is only a minor part of the total cost of lens production, the volume of interest that has been shown in the recent additions such as the Sigma 10-20mm DC ultra-wide zoom, if converted into sales, (and Sigma are struggling to fill back orders still!) will go a long way to keeping the prices down. And the number of cropped sensor cameras already out there on the street is sufficient to continue to fuel the research into further development of these type of lenses.

Another aspect of the argument, and one that sometimes gets overlooked is that of file size and storage. All the increases in pixel counts have, to date, been kept up with by the computer system manufacturers increases in storage media capacities, and to some extent fuelled by them. Digital capture allows and even encourages the taking of more pictures. And more pixels means bigger files sizes. But what, or where, is the limit?

The answer, in most cases, is to what end use the images are being put to. Top end professionals will always require the absolute top end gear suited to their specialisation, immaterial of cost. High fashion and advertising photographers, if they are willing to come down from medium format, will want the largest format available and will therefore choose full-frame. Sport photographers shooting for an output in newsprint will choose the fastest reacting camera, immaterial of frame size but will often appreciate the extra length the cropped sensors appear to give their lenses.

The majority of social photographers will be perfectly happy with cropped sensors once they realise that the picture quality is up to the size of the prints they offer. And those of us that take our pictures purely for our own pleasure will make our own choice but for many of us, cropped sensors will more than suffice when you think that a print of 21”x14” can be printed straight out of the camera from a 12mp 1.5x crop camera. (Nikon D2X at 200dpi)

And let us not forget that one of the biggest names in photography over the last century, Kodak, have already had a couple of goes at full frame top end digital and decided that the market, for whatever reason, is not there. (Although they are rumoured to be preparing another attempt!)

 Who have we forgotten? Well there is the merged companies of Konica-Minolta, who for various reasons did not jump into the digital SLR market until quite late and although they produced a couple of contenders, both with cropped sensors, they didn’t make it and have been bought out by Sony, a big hitter in electronics to further develop dSLR technologies. But Sony have not said if this will include full frame. Pentax too, were not quick but have now produced a number of cameras in succession, with more due soon and all with similar sensors and the Olympus brand with the supposedly universal 4/3rds fitting that has a 2x crop! And of course there is the Sigma SDxx ‘series’ of two with what is probably the best sensor of the lot in some senses at a 1.7x crop.

On balance then, I think that cropped sensors are here to stay, big time!