A body with a hump: necessity or eyesore?
Samsung NX10 is the first camera of its kind which incorporates a viewfinder in the camera body. Some photographers question the necessity of doing this but to me, a viewfinder is necessary for photography.
Using a viewfinder at least looks cooler.
This personal preference is rooted in twenty year of using a SLRs. There are two cogent argument for using a viewfinder. First, a viewfinder allows the photographer to concentrate on doing the technical tweaking for the shots. Just because this is the case doesn't mean that the LCD (AMOLED in NX10's case) screen can't do the trick. But in comparison, seeing the scene through the viewfinder can effectively afford the photographer to feel the scene much better.
The Benefits of the Viewfinder
This is because the viewfinder offers the man and woman behind the camera an exclusive space to mind their own business and envisage the final image without the interferences of the superfluous elements in the scene or the busybodies' irritating peeks of the LCD screen for what is being shot.
Here, an extra argument relevant to digital camera is that the viewfinder saves the photographer's guesses of colours of the final images under bright lights. By way of the viewfinder, the photographer can tune the exposure to exactly what best suits his or her tastes.
But, to make this arguments valid, the implementation of the viewfinder should factor in several considerations which the NX10 meet only partially.
The NX10's Integrated Viewfinder
Bigger external humps?
First, the inclusion of a viewfinder should not stuff the camera body in a way what mums may stuff a turkey for Christmas. Simply put, the viewfinder should not make the camera too bulky which would defeat the purpose of having such a compact camera.
Samsung strikes the right balance between this factor and the useable size of the viewfinder. The fact that NX10 has a lumpy top to house the viewfinder may not suit the taste of some. But, if compared to the option of an external 
viewfinder for photographers preferring one anyway, the monolithic design is more handy and, in fact, more compact.
Eye Sensor and Toggling
As discussed in an earlier post, there is an eye sensor right below the viewfinder of the NX10. Once it detects an object (i.e. your eye) moving close or away, it will toggle the display between the viewfinder and the AMOLED screen. This is a smart design and saves the photographers the troubles of manually switch between the two displays.
« Fast moving
But there is a shortcoming in this implementation. Although the viewfinder and AMOLED screen toggles on and off almost simultaneously, there is a very short time lag the scene is displayed. If you need to suddenly hold the camera to your eye to shoot fast-moving subjects, say, kids, this lag can screw up your shots.
So, this is for Samsung: there should be an option to turn off the eye sensor and restrict the display to the viewfinder.
Mysterious Behaviours
Properly owing to the screen size difference, the viewfinder (921k dots, same as GXR's viewfinder) doesn't really look as sharp as the AMOLED screen (614k dots) – with the diopter adjustment corrected for sure. But tuned brighter up, the viewfinder displays the image and scene nice enough. On the whole, the top-down order of visibility of viewfinder is GXR's, NX10's and GF-1's.
Another puzzling performance of the viewfinder of the NX10 is that it doesn't brighten up the scene in proportion to the increasing exposure value when the scene is dimly lit.
That is to say, for an adequately lit scene, underexposing or overexposing it gradually causes the viewfinder to display the scene increasingly darkened or brightened up.
The scene was displayed in the viewfinder just as this dimly-lit, rightly exposed image looks.
However, for a dimly lit scene, doing the same causes the viewfinder to display the scene correspondingly darkened but NOT increasingly brightened up. The scene will look brightened up in proportion to the exposure transition from a negative EV to the zero EV value. But from there onwards to +EV and even BULB, the viewfinder doesn't oblige to increasingly brighten up the scene.
Overexposing the scene resulted in an image like this. The scene was supposed to look likewise in the viewfinder but it didn't. This doesn't happen except for dimly-lit scenes.
This puzzling performance is the same for the viewfinder and the AMOLED screen. So, there is a bug to fix here.
Bottom Line
Prejudices are personal; so are preferences. But coming from the film camera era, I just find the viewfinder a better instrument for composing and making exposure adjustments for my shots. The benefits are many: the photographer can be more focused on the scene to feel it; the scenes are already framed just as in the final images which is helpful for composition; the camera can be steadied better being pressed against your brow ridge; the bright sun won't blur the visibility.
Samsung made an honourable decision to integrate the viewfinder in the camera body. You know, an extra viewfinder is an extra source of profits. It will not be cheap too. It even seems that the cost is not added on to the price tag of NX10, which is actually very affordable.
Of course, we photographers always wish for a dream camera: Samsung, just try to squeeze the next camera body a bit without taking out the viewfinder.
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