DX vs FX

Comments

• bruto

  July 2016 edited July 2016

  FX is the format approximately equal to 35mm film. DX is a smaller format, approximately equal to APS film.
  
  A DX format is, essentially, a 75 percent crop of an FX image. Because of this, the field of view is different. What an FX camera sees using a 50mm lens will be approximately what a DX camera sees using a 35mm lens.
  
  All FX lenses can be used on a DX camera. A part of the image circle will not show on the sensor, but the lens will behave correctly in all respects. The focal length of a lens is always the same. Thus, for example, you can get a 35mm DX lens or a 35mm FX lens. On a DX camera, both will behave the same, and have the same field of view. On an FX camera, the DX lens will not cover the plane completely and will have dark corners, simply because its image circle is suited only to DX.
  
  If you are planning to stay with DX format for a good long time, DX lenses will tend to be smaller, lighter, and cheaper, while still behaving well. FX lenses will work fine, but will tend to be bigger and more expensive. In some cases, no DX specific lenses exist, and you must use FX. For example, if you want a long telephoto zoom like the 200-500mm Nikkor, there's only one, and it's FX. I use one of these on my DX camera, and it rocks.
  
  In addition, if you get really interested in older Nikon equipment, and adventurous in the use of manual lenses (no meter, no AF, but they work), you will find that some FX lenses that were only so-so in FX format are better in DX format, because DX format only uses the center portion. Lenses that had mediocre or poor edge performance on FX are sometimes better on DX.
  
  If you have a serious expectation of switching to FX format soon, then FX lenses might make more sense, since they can be moved to the next camera body. But I would not bother with this unless you are looking at expensive lenses, and seriously considering a move to FX. Nowadays there are some very fine DX cameras anyway, and the move to FX is becoming less tempting.
  
  I believe Canon has some models that take only one or the other lens, but Nikon lenses are all the same F mount, so FX and DX lenses are always interchangeable.
  
  As for what lenses you need, the kit lens is a good start. You can take many good photographs with it, and get used to how it all operates. It's cheaply made, but sharp and performs well. If you find you want more low light capability, and like a single, normal focal length, the 35mm f/1.8 prime lens is very good, and very popular. Many people like a prime (only one focal length, no zoom) lens, for the extra speed, sharpness, and package size. If you find you are too far away from things, a good adjunct to the kit lens would be one of the relatively inexpensive longer zooms, such as the 55-200mm or 55-300mm, which will get you more telephoto reach.
  
  As for the terminology, in the case of the kit lens in question, DX means it's suited only to DX format. AF-S means it has a focus motor built in (necessary for auto focus on the D3xxx and D5xxx family of cameras which have no focus motor in the camera). 18-55mm is the focal length range. 18mm is a fairly wide angle, and 55mm a very slight telephoto. 35mm would be "normal" for DX. "1:3.5-5.6G" refers to the aperture of the lens. At 18mm, its widest aperture is f/3.5, and when it zooms to 55mm it reduces to f/5.6. The smaller that number, the 'faster' the lens, which means its aperture opens wider, allowing more light in, at the expense of depth of field. The letter G designates this lens as not having a manual aperture ring. It can be set only from within the camera. All AF cameras are fine with a G lens. If this is the regular kit lens for the D3200, it will also have "VR" which is vibration reduction, allowing you to get a clear shot at a slower shutter speed than otherwise.
  
  Note that on this lens, as on many other lower-end AF lenses, you cannot manually adjust the focus when the lens is set to AF. Do not force it. If you need manual override, turn off AF.
  
  There are a number of resources on line to get the basics of what all this stuff means. One that works pretty well is "Cambridge in Colour" which you can look up in Google. They have some basic lessons in aperture, shutter speed, ISO and so forth. It may seem daunting at first, but it's all pretty rational, and once you know the stuff, it will make plenty of sense.
  
  Remember that this is a digital camera, and that means you can take lots of pictures and erase them. While getting educated about all the different operations, don't be shy about trying everything out and making lots of mistakes. Don't know how aperture and depth of field interact? Put it on Aperture priority, and take the same picture at a bunch of different apertures. Don't know how shutter speed affects moving subjects or camera jiggle? Put it on Shutter priority and take the same picture at a bunch of different shutter speeds. Don't know how focal length affects things? Take the same picture at different focal lengths, and so on.
  
  Even if you don't understand everything, make sure you practice finding out where everything is on the camera. Can't make up your mind what ISO to use? That can wait, but make sure you know how to find the ISO, where the Auto ISO is turned on and off, etc. Can't decide on an auto focus mode? That can wait, but make sure you know what is there, and how to find it. Even if there are a million things to learn, you'll be better off (and dollars to donuts you'll be better off than many of your fellow students next month!) if you just know your way around the camera.
  
  And finally, my standard warning, the printed manual for the D3200 is not the complete manual. Many things are left out. The complete manual is on the accompanying CD, in PDF form. Get that PDF and put it on your computer, so you can refer to it as needed.
• Haggis

  July 2016 edited July 2016

  REF Nikon
  In digital SLR cameras, the camera's format refers to the size of its image sensor. Nikon makes a DX-format sensor and an FX-format sensor. The DX-format is the smaller sensor at 24x16mm; the larger FX-format sensor measures 36x24mm which is approximately the same size as 35mm film.
  
  So you should buy Dx lenses, which can be good deals at times. Build up your lenses when you see good deals; Sigma, Nikon, and Tamron all do promotions that can save you lots. The AFS is for auto focus Silent motor on Nikon. Vibration reduction helps with hands shaking with nerves or cold days. If you are using a tripod switch the VC off or you will get blurry photos.
  Sigma 18-250mm f/3.5-6.3 DC MACRO OS HSM is excellent as the Tamron 18-200mm f/3.5-6.3 Di 2 VC Model b018n
  You could also consider a 2x tele converter such as the Kenko 2x teleplus MC7 DGX. Do not use a Sigma 2x on Nikon lenses or a Nikon 2x on a Sigma lens, however the Kenko is fine on either. Reason is that the exposures are not right due to firmware.
  
  My advice is to look at depth of field, and exposure relationships between depth and light. Have fun.
• emozingo

  July 2016 edited July 2016

  Thank you @BRUTO and @HAGGIS for your responses! In the relatively near future I would like to expand past only the kit lens. Just coming into it I'm not yet sure of a "niche" in my shooting but would like a good all purpose lens. What do you think of the AF-S DX Nikkor 35mm f/1.8G as a next step? @BRUTO is that what you meant by 35mm f/1.8?
• bruto

  July 2016 edited July 2016

  Yes, the 35mm f/1.8G is what I meant. This is a basic, prime lens of what would be considered normal length on the DX format. Normal length means that although the field of view is narrower than what you see yourself, the perspective will appear normal. Things will be proportioned more or less the same as they appear to the eye.
  
  Perspective varies with focal length (you can play with this on the kit lens). When the lens is very wide, perspective is exaggerated - close objects will seem much closer and larger than far objects, which will seem very far away. When the lens is longer, perspective will seem to be compressed - close and far objects will seem more the same size and closer together.
  
  Most people who get that 35mm lens really like it. It's very sharp, very well behaved, and reasonably fast. Although there is some limitation to a single focal length, it also helps you to concentrate on what is in the picture, and many people find it an aid to good composition. You have to think about what is and is not included, slow down a little, and move around a little more to frame things.
  
  My usual disclaimer: I don't have this lens, not because of any problem with it, but because I have other lenses. I do like a 35mm on my D3200.
  
  If you're more inclined to a narrower viewpoint and portraiture, the 50mm. f/1.8 (FX works on both) is another inexpensive prime to consider. The 35mm is likely to be more versatile, but for a little while you might want to use the kit lens, and keep track of what focal lengths you find yourself using the most.
  
  @haggis has more experience than I do in third party lenses and teleconverters.
  
  He is right about VR (or vibration control, nomenclature varies with brand). Generally speaking, it's best to turn it off on a tripod, and also may be better off when you're using a very fast (1/500 or faster) shutter speed. Nikon's latest lenses claim to be able to sense when on a tripod, which makes it handy if you forget, but it's still better to turn if off if you remember.
  
  
• emozingo

  July 2016

  Awesome thank you!
• Haggis

  July 2016 edited July 2016

  Try the Nikon AF-S 40mm Micro f/2.8 DX G Lens.
  This is right between the 35mm and the 50mm and the 40mm is a 1:1 macro, and very good for day to day all round.
  So you get 2 lenses for the price of 1. Slightly dearer, but great.
  I have a few Nikon lenses, a couple of Sigma, and one Tamron.
  Buy Nikon when you can. I hate to say it but the Tamron 18-200mm is great when you are travelling light.
  All the best from Glasgow Scotland.
• bruto

  July 2016 edited July 2016

  The 40mm mentioned above is said to be very sharp. As a true macro it's not optimal, because the distance to the object is pretty short, so things like bugs and butterflies are hard to get, but as a very sharp normal lens that does the occasional macro it's hard to beat. Although f/2.8 is not blazingly fast, it's quite decent for low light performance.
• Haggis

  July 2016 edited July 2016

  Bruto, between us, we should keep things going in a positive direction (respect). You are correct that you need to get quite close for macro, but for still subjects it works well.For the extra cash it is a winner.
• bruto

  July 2016 edited July 2016

  @haggis, I agree that this is a winner of a lens, especially if you're looking for something in the normal range anyway. Simply as a macro, the short length is a mixed blessing. Living things tend to fly away when you get too close, but a shorter lens will have more depth of field. If you're already well equipped in the normal range, I'd go for a longer macro, but if looking for a fine start in prime lenses, the 40mm is likely to be well worth the extra 80 bucks or so, and the close focusing is something you'll never be sorry to have.
  
  It's also useful to remember that 1:1 macro, especially on DX, is very very close indeed. Most of the time you will not need to get so close, and working distance may be less of an obstacle than it seems. Even if most of the time the close focus of the 35mm is good enough, there are times when you wish you could get a little closer, or not have to pull back that extra couple of inches, and extra close focus just makes life easier.
  
  My usual disclaimer here: I have none of the usual prime lenses, relying instead on an odd assortment, which may influence my opinion. At this point I have no AF lenses in the normal range at all except for the kit zoom. My "normal" lens is a manual preset 35mm f/2.8 PC. I'd be interested in being able to try out the 40mm alongside the AF 35mm. From what I've read both are pretty hard to fault.