Showing posts with label CX. Show all posts
Showing posts with label CX. Show all posts

Saturday, January 25, 2014

Are Nikon 1 cameras worth the investment? - A kind of review of the 32mm f/1.2 lens

With better and better phone cameras, the market for small point-and-shoot cameras shrink. A small camera is often not much better than a phone camera, and in a few cases it may be worse.

One of the attempts at capturing the low end or mid range camera market is the Nikon 1 series - mirrorless cameras with exchangeable lenses. They produce very good results, just like many phone cameras. Often a Nikon 1 takes better photos than a phone, but it will not fit in a small pocket. While many nowadays always carry their phone around, they often do not bother with a camera.

The question then arises if it is really worth it to invest in a Nikon 1 system.

Personally, I will say it is, if you get the 32mm f/1.2 lens. It costs a fortune, about three times the cheapest Nikon 1 camera, but it opens up possibilities that one does not have with other lenses. As an example, look at the photo below, taken inside Kunsthaus Zürich in dim light. With any other Nikon 1 lens, one would have had to crank up the ISO above 500, something that would have meant a grainier photo. In addition, it would have been difficult to isolate the sculpture in the front from the painting in the background, as no other Nikon 1 lens can achieve such a shallow Depth of Field as the 32mm f/1.2.

In the Background: Ferdinand Hodler's painting Heilige Stunde (1907). In the foreground: Aristide Maillol's sculpture Monument à Cézanne (1907). I have no idea why it is called like that. It does not look like him very much. Didn't Cézanne have a beard?

Another example of the shallow depth of field of the 32mm f/1.2 is this panther chameleon sitting peacefully on a twig. The shallow depth of field makes the eye focus on the chameleon in the foreground. Another chameleon in the background is so fuzzy that it can almost be taken for a dark leaf.

Panther chameleon, Furcifer pardalis. Photo taken in the Masoala Regenwald in Zürich Zoo.

Finally an example of shallow depth of field of some painted glass. The painting on the front of the bottle can be distinguished from the painting on the back of the same bottle, due to the shallow depth of field. This would hardly have been possible with another current Nikon 1 lens.

Painted glass bottle from le Musée de l'Œuvre Notre-Dame in Strasbourg. 

Does this mean that a Nikon 1 serves no purpose with other lenses than the 32mm f/1.2? No, they are decent cameras with most lenses, but the number of situations where they are better than a good smartphone goes up if one gets the 32mm f/1.2. Hopefully Nikon will provide other equally good lenses in the future.

Saturday, January 18, 2014

Old Camera with Big Sensor - New Camera with Small Sensor

There is a widely accepted view that large camera sensors produce better pictures. In Nikon terminology, that means that a big FX sensor is better than a smaller DX sensor, which is better than the really small CX sensor. That is true in most cases. However, when one compares old cameras with new ones, occasionally the roles are reversed.

Some examples using DXOMark's criteria:

The 2012 DX camera D5200 vs the 2007 FX camera D3:


That's a five year difference. The DX camera has a better overall score, but it still lags behind the FX in some areas, like low-light ISO.



This is an eight year difference, and even though the CX Nikon 1 has an overall advantage in DXOMark's rating, it still lags behind the larger sensor when it comes to low light.

Like all comparisons, this is not the whole truth of course. There are many other aspects on cameras than what is measured by DXOMark. The point is simply that for certain things, new and small can be better than old and big, even when it comes to camera sensors.

Monday, April 30, 2012

FX - DX - CX - Why does the sensor size matter?


There is one not so obvious difference between Nikon cameras, and that is the sensor size. The sensor is the part of the camera that senses incoming light. Some high end cameras have big sensors and low end cameras tend to have small sensors.

There are three main sizes with Nikon cameras with exchangeable lense: FX, DX and CX. The big FX sensors are used in cameras like D3, D4, D700, D800. DX is used in cameras like D3200, D5100, D90, D300. The smallest CX sensors are used in J1 and V1 cameras.

A Nikon lens made for a big sensor works with any smaller Nikon sensor. This means that any Nikon lens fits a CX camera - in theory. (You need an FT-1 adaptor, and autofocus may not work and there may be some other limitations.) A DX camera can take both FX and DX lenses. An FX camera only works well with FX lenses.

The focal length of a lens does not change with the camera. This means that magnification, zoom and angle of view are the same for all lenses with the same focal length on that camera. If you take a 200mm CX lens and a 200mm DX lens and a 200mm FX lens and put them on the same CX camera one after the other, the magnification is identical for all of them.

However, the same 50mm lens magnifies more on a small sensor than on a big one. In the picture below there are three shots of the same object with the same lens and focal length, but three different cameras. 


The FX camera (a D800) covers the widest angle. The DX camera (a D5100) covers a smaller area. It has been given a green cast to make it stand out from the two other photos. The CX camera (a J1) covers just a small fraction of the FX area. (The photos have been resized to overlap, so the density of the pixels does not correspond to the size of each photo.)

If I had wanted to cover the same angle of view with each photo, I would have had to choose different focal lengths. If the FX camera uses 200mm, the DX camera would need to be 133mm and the CX camera 74mm to give the same angle of view (or zoom factor or magnification). A table with conversions of some common values can be found here.

Advantages with large sensor cameras:
  • Less noise, better dynamic range and colour depth. This is basically because the sensor has a bigger area to gather information from. However, note that a new camera with the latest technology and a small sensor can perform better than an old camera with a big sensor in these respects.
  • Wider angle of view. To get the same angle as a 14mm lens on an FX camera, you would need a 9mm lens on a DX camera.
  • Narrow Depth of Field and more appealing bokeh. This is actually a tricky one. If you look at the three superimposed photos above, you will notice that they have more or less the same amount of bokeh on the background. That is because they were taken with the same focal length and the same aperture. In this case the bokeh is identical, but the image area is different. It is only when you try to cover the same image area with different sensors that the difference in depth of field is apparent. The FX camera has a focal length 200mm. To cover the same area, the DX needs 133mm. With a smaller focal length, the same aperture value (e.g. f/1.4) actually corresponds to a smaller physical aperture hole measured in millimeters. A smaller aperture hole means a sharper picture overall. Therefore, to get the same depth of field at a smaller focal length, the aperture hole needs to get bigger. If an FX camera has focal length 200mm with aperture f/1.4 with a target at five meter, a DX camera will need to be set to 133mm to get the same angle of view. To get the same depth of field, the aperture may need to be set to something as large as f/1.0. As hardly any Nikon lens has an aperture f/1.0, the same depth of field is impossible on the DX camera. Ergo, FX has a narrower depth of field.
Advantages with smaller sensors:
  • Smaller, lighter and cheaper lenses possible.
  • Smaller camera. (This is not always the case, but an FX sensor will not fit into a really small camera.)
  • Cheaper than big sensor cameras.
  • Wider choice of lenses.
  • Less vignetting in some cases. (If you use an FX lens that has visible vignetting on an FX camera, the DX sensor will cut that part out.)
  • Bigger magnification. (To get the same zoom as a 200mm lens on a DX camera, you need a 300mm lens on an FX camera.)