Conversion of Zoom Rates for FX, DX and CX sensors

Nikon has three sizes of sensors for their current models of cameras with exchangeable lenses. The same lens gives different angles of view depending on which sensor it operates on. If you, for example, like using a 50mm prime lens on your D700 camera (FX sensor) and you want to use a lens with a similar width on your D5100 camera (DX sensor), you should get a 35mm lens. (You should actually get a 33mm lens, but that does not exist, and 35mm should be close enough.) More about that here.

The table below gives some common focal lengths in mm and their equivalent with other sensors.

Sensor type:	FX	DX	CX
Crop factor:	1	1.5	2.7
	28	19	10
	50	33	19
	70	47	26
	200	133	74
	270	180	100
	300	200	111

Some cameras with FX sensors are: D700, D800, D3, D4,

Some cameras with DX sensors are: D300, D7000, D5100, D3200, D40, D50, D60, D70, D80, D90

Some cameras with CX sensors are J1, V1.

Nikon J1 - Why I Love this Hateable Camera

Very recently, I defied my waning bank account and once common sense, and bought a Nikon J1 camera with two lenses: the 10mm prime and the 10-100mm zoom.

The camera has one big advantage with the 10mm pancake lens: it is small. It is so small that it fits in a trouser pocket. Almost. I cannot actually walk or sit down with the camera in the pocket, but I can push it in, and with some effort I can usually pull it out. The fact that the camera is only almost small enough, is one of the frustrating things with the camera. Realistically, I need to carry it in its strap or in a jacket pocket.

Then there are all the other limitations. Forget about zoom. Forget about flash - especially off camera flash. Forget about quick adjustments of ISO, aperture, shooting mode (PSAM) or auto-focus options. There is no nice grip, no swivel screen and the battery life time is not very good. If one wants any of that, one has to use another camera.

But if one wants to simply take a picture, it works fine. It is easy to take sharp pictures that are not too grainy. And there is one unexpected bonus: Nikon's ML-13 remote control happens to work. With a Gorillapod or a Manfrotto table tripod 709B attached, it is extremely easy to just put the camera on a table or floor and trigger a photo with the remote.

10mm is slightly too wide for my taste, but it works. One just has to take one step closer to the target. 10mm on a J1 is roughly equivalent to a 18mm lens with a DX sensor or 28mm with an FX sensor.

10-100mm lens. 31mm focal length. ISO 100, f/5.3, 1/1250s. There is no denying there is some potential for bokeh in this camera and lens. It is not much, but it is much more than none.

Then there is the 10-100mm lens. The range is almost the same as the DX 18-200mm lens or the FX 28-300mm. There is no way the camera will fit in any normal pockets with that lens on. In fact, with the 10-100mm lens, you can forget about the camera's size. The camera is just a little adornment at one end of the lens. The best way to hold the whole thing, is to put the lens in a comfortable position in your left hand, and then fumble around with your right hand, until you get to the little camera at the end, and press the trigger button.

This lens is sturdy. The zoom is electric, but very, very quiet. It is apparently built for movie recordings, so we still photographers pay a lot for features that do not matter that much. But just hearing the absence of sound when you zoom, or feel the weight in your hand is a pleasure. And I love lenses that have internal zoom, so they do not change size when you zoom in and out.

It would be silly to complain too much about the weight and size of the 10-100mm. It is much smaller than Nikon's 70-200mm for example. When it is switched off and retracted, it is shorter than 100mm. (There is a function to keep it expanded, even when it is switched off, to save battery.) However, considering the large diameter of the 10-100mm and the fact that there is no good grip on the J1 camera, it is not that convenient to carry it around in your hand, especially not if you have short fingers.

All in all, the J1 with the two lenses is acceptable for travel shooting, at least for destinations where you can come back later with a DSLR and take some serious photos.

10-100mm zoom lens, 58.2mm focal length, ISO 100, 1/320s, F5.6. Handheld. There was no problem at all to get this sharpness. I in fact got much more keepers with the J1 in this Marathon than I usually do with my D300 and a 70-200mm lens.

10mm prime lens. ISO 100, f/7.1, 2.5 seconds. Taken with an ML-13 remote and a Manfrotto 709B tripod.

How to live with the ergonomy of a D5100 or other "low end" camera

One reason to buy a "high end" or "professional" camera like a Nikon D3S, D300S, D700 or even a D90 or D7000 is that it is easy to change common parameters. It is also easy to change some less common parameters. The chances are that if you want to change a particular setting, you can do it without going into the monitor menus.

But what if you bought a "low end" camera, like a Nikon D5100? How do you quickly change settings there? Well, funnily enough, the chances still are that you can do them without going into the menus. Arguably, the most common changes you will make are shutter speed and aperture, and you do that almost as easily on a D5100 as on a high end camera.

There is no denying that several settings are easier to reach on a high end camera. There may be some settings you have chosen to change all the time in your daily shooting that are cumbersome to change on the D5100. But if Nikon have done their user studies correctly, most people should be reasonably happy with the ergonomy of the D5100.

Let's have a look at the difference in buttons between the D5100 and a D7000 or a D90. The D7000 and D90 have dedicated buttons for the following functions, that are not by default easy to access on a D5100:

1. ISO
2. White Balance
3. Release mode (one picture, many, etc.).
4. Bracketing button.
5. Quality button.
6. Metering (spot, matrix, center weighted).
7. Autofocus mode (single-servo, face priority, subject-tracking, etc.).

For the first five of these, the photographer can select one of them to be assigned to the fn button on a D5100, which makes it easier to access them. I change the ISO all the time, but rarely the other ones, so the choice is easy for me.

For the Metering and Autofocus, they can be changed directly on the Monitor without going into the menu system on the D5100. It is admittedly more cumbersome than on the D7000 or D90, but even on those ones, you often have to take the camera down from your eye to look at the top LCD screen to see which values you choose.

And when it comes to ergonomy, a large number of buttons is not necessarily good, as the photographer will have to learn where they are, and s/he is likely to occasionally press the wrong one, as the choice is so big.

This does of course not mean that a D5100 is as good as a high end camera. It is not. It lacks plenty of functions, and one does not have to be that experienced a photographer to take advantage of the additional buttons of a higher end camera.

However, if weight or price or a swivel screen are important factors, one should not discard the D5100 for its bad ergonomy. It is not a perfect camera, but to most photographers in most situations, its limitations should be acceptable.