5D Mark II and 550D lens distortion

[James Winslett]

Hi all,

I'm shooting a dance performance next month and I'm intending to shoot from as far away as possible with a telephoto lens in order to minimize distortion. I shot some test footage at the dance studio last week using a 550D with the stock 18-55mm EF-S lens and as suspected the 18mm shots from the middle of the studio gave the dancers the full width of the room to play around in but were greatly distorted, while the 55mm shots from the back of the studio looked great but restricted the dancers' lateral movement to about 4.5 metres, which is a bit too limiting.

Using an online angle of view calculator, I discovered that shooting from the same distance with a 5D Mark II with the same focal length of 55mm would give the dancers 7.2 metres freedom of movement from left to right, I'm assuming because of the larger sensor. What I'm not sure about is whether I'd be again facing an increase in the amount of distortion or whether I'd effectively be getting the best of both worlds.

Any advice would be much appreciated.

Thanks,

James

[Greg Fiske]

How about taking the footage into photoshop and correcting the distortion? ->smart object->lens correction.

[John Wiley]

It will come down to individual lenses.

The EF-S lens you mention will not even mount on the 5DmkII which only accepts EF lenses. If it did mount, you would see extreme vignetting.

If you were to use a lens designed for a full frame camera, such as the 24-70 (not a cheap example!) then at 55mm you would probably find it looks really good.

Most zoom lenses suffer from distortion, and the bigger the zoom range is the more apparent it generally is. Some lenses might have barrel distortion at wide and pincushion distortion at full zoom. Others might be worse in the middle. Also some wide lenses are designed to be rectilinear - that is, they keep straight lines straight, but it can also look unnatural - think of those architecture shots where right angles look acute but the lines stay straight. These lenses work really well for scenes that are locked off such as what you are shooting, but when you pan over certain objects such as a brick wall things get bizarre - objects appear to stretch outwards as they move towards the edge of the frame.

The fact that the 5d has a wider field of view does not mean you will experience more distortion with any particular lens. However it will allow you to see more of the edges of the lens' imaging circle - the area where distortion is generally most apparent. A well designed lens, however, will not appear more distorted on a 5D than on a 550D.

[James Winslett]

Thanks John,

I didn't know you could get rectilinear wide-angle lenses. I want to limit the amount of the background visible behind the dancers though, so something around the 55mm mark seems about right to me. Would 55mm on the 24-70 be fairly distortion free or do you think I'd be better off opting for one of the 50mm primes. I'd just be hiring the lens over the weekend of the shoot, so the cost won't be much of an issue.

[James Winslett]

Thanks, Greg. I'll check that out too.

[Antti Turpeinen]

If you're looking for long telephoto lens for video work check out Nikkor 180mm f2.8 ED-AIs. Very nice glass and not too high priced. Works well on 5Dmk2 fullframe. Great pic quality, nice bokeh and wonderful mechanics. I DO sound like a salesman, sorry bout that.... The Canon 200mm f2.8L is also very good lens I hear and see pics, but for video I'd go for something bit more manual/mechanics/video work I'd go for Nikkor. I do not have or own the Canon 200mm.

I'm suggesting these longer lenses as you were talking about telephoto. 55mm (on crop body) or 70mm on fullframe is medium telephoto. Go for the long lens and use a stable tripod.

[James Winslett]

Thanks, Antti, those lenses look great, but it's an indoor shoot and I think they'll be a bit too long. The furthest I'll be able to place the camera from the dancers is about 13 metres, so I think what I'm actually after is something more in the middle. I should have stated medium telephoto in my original post - I'm still learning all the terminology.