How do I know if my crop sensor is a factor?

[e.rose]

I'm day dreaming and looking at lenses (or what I like to call deciding on what I want so I have a goal to save for... ) and I've finally gotten myself to a point where I feel safe enough to venture into the non-canon brand lenses.

But now I have a question...

I'm shopping for a lens that will give me a wider angle... however I'm shooting a crop sensor camera, so I know I need to take that into account when looking at different lenses and their focal lengths.

Canon makes it easy for me... I know EF cameras aren't going to be what they say they are on my camera (for example my 50mm is actually giving me 80mms) and that EF-S lenses will give me what they say they will.

But how do I know what's what as far as Non-Canon lenses go? What in the specs should I specifically be looking for? Because so far I haven't seen anything distinguishing Full frame lenses from crop sensor lenses... unless I'm just not understanding what I'm seeing.

 

[Rosshole]

It is all relative...

you have your 18-55... so a 10-24 would be much wider than you are used to...

 

[Big Mike]

They are all what they say they are (not counting slight differences for certain lenses).

So a 50mm Canon lens, will give you the same view as a 50mm Tamron lens, same as a 50mm Sigma lens, same as a 50mm Mikebrand lens etc.

for example my 50mm is actually giving me 80mms

That's the wrong way to think of it. Your 50mm is giving you 50mm (on any camera), it's just that your 'crop' camera, isn't seeing the edges of what the lens is seeing.

But how do I know what's what as far as Non-Canon lenses go?

Other companies, such as Tamron/Sigma do have their own version of EF-S lenses. The focal lengths (and thus field of view) are the same as Canon....and the same as 'full frame' lenses of the same focal length. They are like EF-S lenses, in that their image circle is only big enough for 'crop' cameras.
Each company has it's own name for such lenses....shouldn't be hard to find. But really, it doesn't matter (because 17mm is always 17mm). It only matters if you plan to upgrade to a full frame camera and don't want EF-S type lenses.

 

[Jarmo]

For example Sigma refers to full frame compatible lenses with the letters DG. DC is for crop sensors only.

 

[eric-holmes]

It doesn't matter with DX. Any DX or FX lens will be ok. It's when you are using an FX camera and a DX only lens when you run into problems.

Did I understand the question correctly?

 

[MohaimenK]

and in the description it'll tell you it's only for APS-C size image sensors

 

[e.rose]

But really, it doesn't matter (because 17mm is always 17mm). It only matters if you plan to upgrade to a full frame camera and don't want EF-S type lenses.

it *does* matter, because I'm looking to get as close to a specific focal length as I can. I understand that a 50mm is always going to be 50mm, but my camera doesn't see it that way because of what you said about the edges being cut off by the sensor.

It doesn't really matter how I'm thinking about it... the fact of the matter is that for me it *is* like using an 80mm.

And I need something wide... so if I buy a 24mm lens that's meant for a Full Frame camera, without realizing it's meant for a full frame, it's not going to be wide enough... because 24 x 1.6 = 38.4. But I can adjust my purchase accordingly if I know that the lenses I'm looking at are meant for full frame cameras.

So I need to know exactly what it is I'm looking at before I buy. :sillysmi:

For example Sigma refers to full frame compatible lenses with the letters DG. DC is for crop sensors only.

Thanks... that actually helps because that's actually what I'm looking at right now I guess I'll have to figure out the right combination of words to pull up the meaning of the different labels for different lens brands on Google.

 

[e.rose]

Did I understand the question correctly?

I don't know. I don't know what FX and DX means.

and in the description it'll tell you it's only for APS-C size image sensors

Gotchya. :sillysmi:

 

[o hey tyler]

Did I understand the question correctly?

I don't know. I don't know what FX and DX means.

FX = Full Frame
DX = Crop Frame

 

[KmH]

Inside of 35 mm, you can effectively change the FOV (apparent focal length) by just taking a step forward or backward.

Seems kind of pointless to fret over a 5 mm or so apparent difference in a wide angle lens when you can change the apparent focal length by just slightly leaning forwards or backwards to get the same apparent 5 mm or so focal length change.

 

[e.rose]

Did I understand the question correctly?

I don't know. I don't know what FX and DX means.

FX = Full Frame
DX = Crop Frame

ooooooh okay.

In that case...

Eric... no.

I know any Full Frame or Crop Frame lens will work on my T2i, but using a Full Frame lens on my Crop sensor doesn't "give" me (and I use that term loosely because I'm aware that the focal length doesn't physically change, but that the sensor just crops out the edges... hence... crop sensor ) the focal length that it says it will...

My 50mm lens is a Full Frame lens... but every image I take with it, is like taking it with an 80mm because of what gets cropped out.

So my question was how do I know what Non-Canon lenses were made for a crop sensor vs. a full frame so that I can make sure I'm purchasing a lens that's going to "give" me the focal length I'm looking for (or at least as close to it as possible), because if I'm looking at Full Frame lenses, I need to take my crop sensor into account.

 

[e.rose]

Inside of 35 mm, you can effectively change the FOV (apparent focal length) by just taking a step forward or backward.

Seems kind of pointless to fret over a 5 mm or so apparent difference in a wide angle lens when you can change the apparent focal length by just slightly leaning forwards or backwards to get the same apparent 5 mm or so focal length change.

It's not pointless when you're pressed up against the front of a stage and literally have no room to step backwards.

 

[Big Mike]

With all due respect...you still aren't getting it.

So my question was how do I know what Non-Canon lenses were made for a crop sensor vs. a full frame so that I can make sure I'm purchasing a lens that's going to "give" me the focal length I'm looking for (or at least as close to it as possible), because if I'm looking at Full Frame lenses, I need to take my crop sensor into account.

The focal length is in the name of the lens. If you are 'looking for' 50mm....then buy a 50mm lens. It doesn't matter which brand, it doesn't matter which designation it has (EF-S, DX, FX, SNFU)...it will be 50mm.

And the only way it 'gives' you 80mm....is if you were expecting it to have the field of view of a 50mm lens...ON A FILM CAMERA.
If you are not used to using a 35mm film SLR (or a full frame digital)....then you do not need to be concerned about the crop factor. The only reason the crop factor exists...is because it's used to compare lenses to the old standard...which was 50mm film cameras.

50mm...on your camera...should be what 50mm is to you. You don't need to think that 50mm is actually more like 80mm...and that 80mm is actually more like 128mm. That's only a comparison.

 

[Village Idiot]

Did I understand the question correctly?

I don't know. I don't know what FX and DX means.

and in the description it'll tell you it's only for APS-C size image sensors

Gotchya. :sillysmi:

Did I understand the question correctly?

I don't know. I don't know what FX and DX means.

FX = Full Frame
DX = Crop Frame

FX & DX are lens mounts, not sensor sizes. The same with EF and EF-S, which are Canon when FX & DX are Nikon. Not relavent in this thread.

If you want a good concert lens, check out 10-11mm on the wider end. I think someone makes an 11-16 f/2.8 That will give you about the same focal length at the wide end as the Canon 17-40 f/4, which I use for concerts. Any wider than that and you're going to be shooting fish eye.

I use the 17-40 at most all indoor club venues where you have stage --> pit -- > crowd with a pit that's wide enough for you to squeak past another photographer without a huge beer gut.

 

[Overread]

It's either Tamron or Tokina who make the 11-16mm f2.8 and from what I've read its a darn fine wide angle lens. It trumps the sigma and canon offerings in that its got that f2.8 aperture.

The widest that I am aware you can go is the sigma 8-16mm but its f4.5 - f5.6 in aperture so not as wide as you might be needing in your indoor low light shooting conditions.