"All-In-One" Lenses - Is It Worth It?

AF-S DX VR Zoom- NIKKOR
18-200mm f/3.5-5.6G IF-ED

Pictured above is Nikon's latest camera lens which covers a focal length zoom range from 18mm to 200mm. It is designed for DX-cropped digital cameras like the Nikon D60, D90, D300, etc. With such a huge range covered within a single lens, why would anyone want to buy multiple lenses to cover the entire focal range?

For instance, you can buy a 17-55mm lens and a 70-200mm lens to cover the range. But these two lenses will cost you a lot more than the single lens. And, these lenses are a lot bulkier and heavier. So why do it?

The all-in-one lens' attraction is:

1. Lower cost than buying two lenses to cover the entire focal length

2. Smaller lens

3. Less weight

4. Carry one lens instead of two

5. VR (Vibration Reduction) Lens - stabilizes camera shake

The pitfalls of the lens?

1. Slow speed (doesn't have very large apertures)

2. Cannot perform low depth of field images as well as other lenses

3. Variable aperture at different focal lengths (not a constant aperture)

At the widest focal length of 18mm on the all-in-one lens, the largest aperture is f 3.5. And as you zoom towards the telephoto range of 200mm, the aperture becomes f 5.6. On the other lenses, regardless of the focal length, the largest aperture is f 2.8. What does this mean? Well, it means that the all-in-one lens is 1/2 stop slower at 18mm and 2 stops slower at 200mm than the other lenses. Because of this, to get the same amount of light to the camera's image sensor, you would have to shoot at higher ISO settings (sensitivity of the image sensor.) While this does not appear to be a big deal for outside photos where the sunlight is bright, it does become a factor in low light situations like shooting with ambient light in a dark church. For instance a shot that would normally require ISO 1600 would now require ISO 6400 at 200mm on the all-in-one lens. At ISO 6400, there is going to be a certain amount of digital "noise" that will be noticable in the image. Not good.

Also while a focal length of 200mm will have a lower depth of field, it won't be as low at f 5.6 compared to f2.8. So trying to get "creative" images that totally blur out the background and foreground in a photograph will not be as easy to do on the all-in-one lens.

Will the VR function of the lens help? It only helps stabilize the shot from camera shake. It does not help in getting you a lower depth of field. Plus to get a similar exposure of the f 2.8 lenses, the shutter speed will have to be 2 times slower than when using an f 2.8 lens at 200mm. For instance if it takes 1/125 second to take a good exposure for one image, that shutter speed would have to be reduced to 1/30 second to get the same exposure at 200mm at f 5.6. Now while VR will help stabilize the camera shake of handholding a lens at 200mm at 1/30 sec, if people move while you are taking the photo, the VR will do nothing to help that. The people will blur. But for the fast f2.8 lens, people could move around if they want because the camera will be shooting at 1/125 second and that's plenty fast of a shutter speed to stop most (if not all) of the small movement of the people. Of course if the people are running and you are taking the photo, they will blur! But in general, with small movement of people, that image is still going to look SHARP, not blurred. VR only helps with your own movement while taking the photo. While it's claimed that with this version of VR, the "system minimizes image blur caused by camera shake, and offers the equivalent of shooting at a shutter speed 4 stops faster," that is only true for shake caused by you when holding the camera. It does nothing for movement blur caused by your subject. But Nikon does not make this clear as it minimizes the potential for sales when presenting the VR function.

So is it worth buying the all-in-one lens? Maybe. If you plan to shoot a lot of images outside where there is plenty of light, and you don't want to keep changing lenses to cover a wide range of focal lengths, and you don't want to carry a lot of heavy lenses, the all-in-one solution is perfect. Often, these lenses are considered "vacation lenses" because it's a LOT EASIER to carry one lightweight lens than two or three heavier lens.

While I would never consider using a lens like the 18-200mm lens for a wedding, I would think twice when it comes to having a single lens for the convenience on vacation. Who wants to travel with all that weight and bulk while on vacation? The 18-200mm is a better choice for its compact size and low weight. It's a compromise...