# How to achieve full-frame look/view on a crop-sensor - without changing the lens?

I have a Canon 600D, which is crop-sensor camera. If you're shooting with a Canon EF 50mm, it'll be (50x1.6) = 80mm on a normal full-frame body right? I'm also a street-photography-kinda guy, which I prefer going on 50mm lens than a 18-55 kit lens for shooting (while in a moving car).

Now, how to achieve that real full-frame 50mm focal look/view on a crop-sensor without changing the lens? I know that 50mm on full-frame is around 30mm on crop-sensor. Is there any other way than changing the lens to around 24 or 35mm?

-
What is this "full frame look/view" you think you're trying to achieve? – David Richerby Jan 31 at 8:26
i would edit the title... "how to achieve the look" and "how to achieve the look without changing the lens" are different questions! – szulat Jan 31 at 9:20
@DavidRicherby the angle distance, within the same focal length, the field of view. – Reinaldy Rafli Jan 31 at 9:24

You can't.

What we refer to as equivalence is only an approximation. You can't put a different lens on a crop sensor camera and get the same shot with the same field of view from the same shooting position with the same depth of field using the same ISO and the same shutter time as you can get with a full frame camera. The converse is also just as true. You can't put an 80mm lens on a FF camera and perfectly replicate the same shot you got with a 50mm lens on an APS-C camera. To get a number of the variables to match, you must be willing to allow other variables to differ.

Having said that, to even begin to get close to the look you can get with a 50mm lens on a full frame camera, you must begin by using a lens with a similar field of view on your APS-C camera. This means a lens with a focal length of around 30mm. And to replicate the depth of field of a 50mm lens at f/1.8 on the FF camera, you must use an aperture of around f/1.1 on the 30mm lens. Unfortunately, there are no 30mm f/1.1 lenses available in the Canon EF mount. If there were any such lenses available they would likely be several orders of magnitude more expensive than any version of an EF 50mm f/1.8. It is quite likely the price difference would be even greater than the price difference between your 600D and a Canon FF model such as the 6D.

-
"The converse is also just as true" - i would say it is slightly less true, as in order to get the exactly same crop look on a bigger sensor you can simply... crop! :-] – szulat Jan 31 at 9:14
@szulat Not usually with the same pixel density, though, unless you are using a Canon 5DS or Nikon D800/810. – Michael Clark Jan 31 at 12:40
yes, of course! I just assumed that nowadays, having the high megapixel sensors, we can often afford to not care about the pixel density as much as we used to do – szulat Jan 31 at 13:36
Which leads us directly back to "...*equivalence* is only an approximation." And "To get a number of the variables to match, you must be willing to allow other variables to differ." – Michael Clark Feb 1 at 5:19

By the way, while the Michael's answer is absolutely correct and practical (you need a new lens!) it might be interesting to learn that you actually CAN achieve the same FF look without changing lens under some circumstances (other than stated in the question - it will not work with 600D and with street photography).

And yes, technically this is a comment, not an answer, but it would be too long ;-)

## First, it might be possible to use a focal reducer.

For example I am using a Sony APS-C + Lens Turbo adapter that makes the 50mm f/1.4 lens behave almost exactly like on a full frame camera (but this is only possible with mirrorless, because of their shorter flange distance).

## Second, taking the APS-C photo, you already have a fragment of the full frame photo, just go on!

Remember that the FF lens still creates exactly the same image when used with APS-C camera... you merely can't see the whole thing because the sensor is too small. So why not move the sensor and catch the full picture step by step?

Traditionally, this is achieved by using a tilt/shift lens (again, just a theoretical possibility, as this is not the kind of lens you have), but today the same effect can be achieved much easier with any lens, just by rotating the camera and adjusting the perspective projection in post.

By stitching the images, you get the exact equivalent of the FF sensor, we can even say the image WAS captured by the full frame sensor, just not all parts at once. Obviously, this method (known as the Brenizer Method) is not practical in all situations.

-
+1 on Brenizer mention. It's a lot of work in post. But generally I really like advice that encourages people to make the most out of what they have, sometimes in very creative ways. That's getting to the distinction between practitioners and artists. – scottbb Jan 31 at 17:41
The Brenizer method when the question mentions they are shooting from a moving car? – Michael Clark Jan 31 at 20:37
"under some circumstances (other than stated in the question)" :-] – szulat Jan 31 at 20:56