I read this article from Kevin with interest because the problems of equipment weight and size can be an issue, especially as one gets older.
However, those of us who are a bit obsessed with fundamental image quality (from the technical perspective) tend to be reluctant to downsize and sacrifice the image quality we are used to and appreciate, at least I am.
When reading Kevin's article, I was struck by the following comment.
Kevin writes:
"The 100-300mm easily fit into this pocket. How cool is that? I was walking around with a 600mm equivalent lens in my pocket." Kevin then goes on to show 2 images comparing the size of a Nikon D800-E with a monstrous Tamron 150-600mm zoom attached, and the Olympus OMD E-M1 with the very much smaller Panasonic 100-300 zoom attached, describing the 100-300 zoom as equivalent to a 200-600 and asking, "Which System would you want to carry all day?"
It occurred to me, when I saw these images, that they are a bit misleading, especially for 'newbies' who may not be au fait with the significance and ramifications of so-called 'full-frame lens equivalence'.
So, out of curiosity and for my own benefit, I've done my own comparison to see how significant are the benefits of a lighter system such as the OMD E-M1, with 100-300 zoom, compared with a D800E, which is a camera I own.
The first point that is necessary to understand, when making comparisons between different formats of cameras, is that there's not necessarily any difference between a manufacturer's crop of the sensor and your own crop of the image from a larger-format sensor, depending on pixel density.
The pixel density of the E-M1 is greater than that of the D800E,. therefore when we crop the image from the D800E to the same size and format of the E-M1 image, so that both images have an identical angle of view, the D800E will have the disadvantage of slightly fewer pixels, approximately 9.4 mp compared with the 16 mp of the E-M1. However, in terms of angle of view, that massive 150-600 lens on the D800E becomes the equivalent of a 300-1200 mm lens in relation to the sensor size and format of the E-M1. Equivalence works both ways.
So, with this in mind, I wondered what the real trades-off would be if we were to compare a D800E with Nikon AF-S 70-300 VR F4.5-5.6, and the E-M1 with Panasonic 100-300 F4-F5.6. (I can't find an exactly equivalent zoom lens of 100-300 for the Nikon.)
The obvious advantage is the lower cost of the E-M1 system of course, but what about the other advantages of weight, image quality and effective zoom range?
The weight of the E-M1 with 100-300 zoom will be about 729 gms lighter than the D800E with Nikkor zoom attached. That's noticeably but not particularly significant for me, especially when compared with the 'effective' wider range of a 70-300 on the D800E, or even a 100-300 if such a lens were available.
One can always crop an image to get a narrower angle of view, but getting a wider angle of view than the limits of one's lens and sensor, requires stitching, which is not always practical when trying to capture the moment, or whenever the subject is moving.
A 100-300 zoom on the D800E gives one the flexibility, in terms of E-M1 equivalence, of a 50-300 zoom. A 70-300 gives one the equivalence of 35-300 mm. That's a much more useful range than 100-300 on the E-M1. In other words, in order to get the same angle of view with a 100 mm lens on the E-M1, as one would get with a 100 mm lens on the D800E with no cropping, one would need to use a 50 mm lens.
So, already that additional 720 gms of weight might be justified. We've effectively doubled the zoom range of the lens on the D800E.
But what about image quality? I think it's reasonable to assume that at maximum zoom, after cropping the D800E image to only 9.4 mp, the E-M1 image at 16mp will be sharper, at least in the centre. At the edges and corners probably not. How much sharper would be interesting to see.
However, the reverse would be true as we move towards a wider angle of view. For example, if one is using the E-M1 at 150mm, one would not attempt to get the same angle of view by using the lens on the D800E at 150mm then crop to 9.4 mp. One would use the lens on the D800E at 300mm, then crop slightly to get a 4/3 aspect ratio if that was desired. A 30 mp image is likely to be significantly sharper than a 16 mp image, and the same applies to all focal lengths between 150 and 50 mm (or 150 mm and 35 mm). There will be some crossover point between 150mm and 300mm where the E-M1 begins to appear sharper than the cropped D800E image. That crossover point might be around 250 mm, but I'm just guessing of course.
In summary, if Kevin had shown an image of the D800E attached to a Nikkor 70-300 lens and asked "Which System would you want to carry all day?", I would have replied, definitely the D800E because of its significantly wider zoom range, significantly higher resolution between 35 mm and 150 mm, and significantly lower noise and higher DR across most of that zoom range.
