Lens Interchangeability

[Jayne3]

I'm sure there is a thread here about this, but I am not sure what search term(s) to use to find said thread, so here goes. (If there is one, and the info is still relevant and up-to-date, please feel free to point me to that thread if you don't want to repeat your answer here.)

I am still doing research on what brand of camera I want, nevermind the individual mode, and have seen here, particularly in some of the "brand-loyalty" threads, that the reason one has stuck with the same brand of camera even after an upgrade (or why someone should) is because of lenses and not wanting to replace all their lenses if they switch brands.

It appears that the lenses are mostly interchangeable between different models under the same brand. Is that correct? What is the main reason that the lens would *not* be compatible with another model camera under the same brand?

Is that the norm, that if one has, say, Nikon camera and lenses, and upgrades their camera, that their lenses will work with their upgrade? Or is that only within a "series" that that is true?

Thanks for any insight into this.
~Jayne

[RovingLenses]

Originally Posted by Jayne3

What is the main reason that the lens would *not* be compatible with another model camera under the same brand?

One example I can quote is the Canon EF and EFS lenses.

The Pro-sumer models like EOS 40,50D ... and EOS 400,450,500..600D can use both EF and EFS mount. However, once you move into the professional range like the 5D or 1D, they can only use the EF mounts. This is mainly to do with the size of the sensors and the crop factor associated with it.

I'm not sure if Nikon has any such limitations, as my knowledge of Nikon is a lot more limited than that of Canon.

~AC

[OsmosisStudios]

Originally Posted by Jayne3

It appears that the lenses are mostly interchangeable between different models under the same brand. Is that correct? What is the main reason that the lens would *not* be compatible with another model camera under the same brand?

As with everything, it depends.

Most cameras on the market right now use a sensor that is 24mmx18mm (or thereabouts). That's half the size of a frame of film (which is 36mmx24mm). Some Pro-series bodies use sensors that are the same size as film.

If you have older lenses from the film days, you're fine: the lenses project an image from the outside onto the sensor that is large enough for both formats. However, most manufacturers have made lenses specific to the smaller format (EF-S for Canon, DX for Nikon, others for third-party) and while these lenses work perfectly on the majority of the bodies available (ie the ones with the smaller 24x18 sensor) they do NOT project an image large enough to cover the larger sensors (36x24). What this means is that these lenses, while compatible with anything from that brand, are NOT compatible with the pro-series bodies.

For instance:
I have 4 lenses. 2 of which are designated "DX" lenses by Nikon, which means they're designed for the smaller sensor in my D300s. The other 2 are "FX" lenses, which means they're designed for film/full-frame sensors of the pro bodies. I can use the 2 DX lenses on any body that has the smaller sensor, but the 2 FX lenses can be used on any Nikon body without limitation.

Here's the trick: With Canon, they engineered the EF-S mount in such a way that it will not physically mount to a pro-series body with a larger sensor: Nikon didn't. In Nikon's case, DX lenses will mount to the larger-sensor bodies, but the camera automatically compensates and "crops" the image to get something useable. This can be turned off, but most lenses will cause dark or black corners on the larger sensors.

NB: Some DX lenses are capable of covering the entire FX sensor size: I know my 10-24 can from about 16mm on. It's not perfect, and the corners do darken, but it covers them.

[Jayne3]

Thanks!

So it appears that bigger is better (ie lenses that are made for the larger sensors in cameras that lenses are downward-compatible) and/or planning everything on the "prime" camera (meaning that even if I cannot afford my dream/perfect-for-me camera, to act as if I can and buy accordingly, then find a pro-sumer/lessor camera that fits those lenses) would be the best way to go, in order to not have to buy everything new if I upgrade my camera.

How often do the individual brands change the mounts on cameras? Or is the mount only changed between tiers (consumer vs prosumer vs pro)?

Thanks again, very helpful.

[OsmosisStudios]

Brands try desperately not to change the mount within the brand: Canon was an exception as it was a complete paradigm shift from manual focus to autofocus and putting the motors in the lenses and so on. That was huge. And they lost a LOT of people to it too.

The mount also doesnt change: its the lenses that do. In Canon's case it's an attempt to make the system "dummyproof", where as NIkon just assumes you know what youre doing and accomodates.

What you buy really is based on what you plan on shooting and your budget. Frankly, I cant see myself going to FX: the cost of lenses pretty much doubles, and the size of lenses does the same. I just dont have the finances to do it, and dont think I ever will be able to justify it. There ARE advantages, btu not to the hobbyist or amateur. Im content with my gear at the moment.

[Jayne3]

So am I to understand that my primary focus (no pun intended) should be to find the lenses that will achieve the result(s) that I want, then find the camera body to match? Same for when I upgrade camera body, if I've spent tons on lenses? Is that the "norm" of how it usually goes?

(Sorry if some of this is trivial; I'm new to dslr and lenses and such, and am also not rich, so I have to buy piecemeal, pretty much, and if I decide to upgrade (or worse, break the current one and cannot get the same model) I -really- cannot afford to buy all over again -any- accessories, lenses included.)

I appreciate all this info; it helps out a lot.

[inkista]

While it would be nice to find the perfect lenses, then get the body that complements them, most folks find that cost alone precludes going to full-frame. The D700 and the 5D Mark II new and body-only are both in the $2500 price range. Most folks, simply from a budgetary point of view, are going to go with crop body cameras.

Originally Posted by OsmosisStudios

Brands try desperately not to change the mount within the brand: Canon was an exception as it was a complete paradigm shift from manual focus to autofocus and putting the motors in the lenses and so on. That was huge. And they lost a LOT of people to it too.

Canon and Minolta/[now Sony]. Pretty much around the same time (early '80s), but each system has been using their respective autofocus mount ever since. And this switch is why there's no focus-motor-in-the-body type worries, as there is with Nikon.

One other thing to keep an eye out for are the brands that offer more than one mount system because they do dSLRs AND they do mirrorless compacts. Olympus does four-thirds AND micro-four-thirds cameras. These are two different mount systems. And four-thirds lenses with an adapter are fully compatible (i.e., maintain autofocus and other electronic communication protocols) on micro four-thirds cameras, but not the other way around. And both systems use the same size sensor.

The Sony Alpha and Sony NEX, similarly also are two different mount systems, and again, the Alpha lenses, with an appropriate adapter, can maintain full function on NEX cameras, but not the other way around.

BTW, rebuying lenses is not a huge deal, if you bought good lenses to start with. Good lenses retain resale value much better than bodies (digital electronics, remember?) do. You can generally sell your lenses and recoup a good deal of the cost of the lens if you kept it in good condition. In some cases, you might even make a profit. This is typically NOT something you can do with camera bodies, since digital electronics depreciate sizably and quickly.