EOS vs Full frame compression & Bokeh
 

We use both the Canon 70D and 5d Mark iis, and we need to make a decision about buying lenses.

I'm wondering if the compression and bokeh will be similar when using a 70D with 135mm f/2.8 versus the 5d mark ii with 200mm f/2.8.

Does anyone have any experience with this?

Re: EOS vs Full frame compression & Bokeh
 

I assume that you meant f/2 for the 135mm lens. If so, they are very close.

Using this DOF Calculator: Online Depth of Field Calculator , APS-C sensor with 135/2 lens at 10 feet gives this result:

Subject distance 10 ft

Depth of field
Near limit 9.94 ft
Far limit 10.1 ft
Total 0.12 ft

In front of subject 0.06 ft (50%)
Behind subject 0.06 ft (50%)

Hyperfocal distance 1574 ft
Circle of confusion 0.019 mm

For the 200/2.8 on a full frame camera, we get this:

Subject distance 10 ft

Depth of field
Near limit 9.94 ft
Far limit 10.1 ft
Total 0.12 ft

In front of subject 0.06 ft (50%)
Behind subject 0.06 ft (50%)

Hyperfocal distance 1547.3 ft
Circle of confusion 0.03 mm

Note the circle of confusion: 0.03/0.019 is 1.58, which is very close to the 1.6 ratio of the sensor sizes.

I used to own the EF 200/2.8L lens. It was excellent! The EF135/2 is from the same family and is said to be even better.

Re: EOS vs Full frame compression & Bokeh
 

Hmm, OK. I did actually mean 2.8, but now see the 2.0. Thank you for the info.

The issue I see now is a lack of zooms with a wide open aperture. For instance, to get a equivalent zoom for the 70-200mm f/2.8, I'd need to find something about 40-135mm. The 24-105mm f/4 is interesting, but I think would be just a bit short considering how far away we have to be at some churches, and how tight we like to shoot the vows.

Guess I'll have to resort to lens changes, or 2 different cameras.

Re: EOS vs Full frame compression & Bokeh
 

Or use the 3x crop on the 70d with the 24-105?

Re: EOS vs Full frame compression & Bokeh
 

Of course, the 24-105 f/4 on a crop sensor with an additional 3x crop will have the reach, but will have a very deep focus compared to 200 f/2.8 on full frame. Also, I've found that crop modes (at least with ML on the 5D2) are noisier than full-sensor modes.

This is for weddings? Got it. I use a 70-200/2.8L IS II at work for company meetings. It's ideal for this use and would be perfect for weddings as well. Our podium is reasonably lit (I add two stage lights, each about 25 feet from the speaker), yet I still shoot at f/2.8 and 320 ISO or so. Churches are often much darker, so I'd be wary of going with an f/4 lens.

Rather than active zooming, I shoot tight with the 200 & 5D. We also use a standard camcorder to capture a wider view. I cut between the two. This covers gaps when I have to stop/start the 5D2 due to the 12 minute limit. I record audio into the wider, master-shot camera. We use a Vinten 3AS tripod for the 5D2 as I track the speaker with it. We use a cheap tripod under the locked down master camera.

Also, for our 5D2, we use the VAF filter. That makes the images nice and smooth, but it makes the lens non-parfocal. When I zoom, focus is quickly lost. That's another reason that I don't zoom. I set it at 200mm and forget it.

Even with the Vinten tripod, Image Stabilization comes in handy. It smooths out microvibrations when I touch the tripod handle.

Anyway, the low noise of the 5D(2 or 3), the f/2.8 speed of the lens, and the IS feature make this an ideal combo for shooting somewhat long at live events. Even with a crop camera, I'd choose this same lens. It would let you go even tighter and/or let you shoot from further away in large settings.

You can also add an extender. Avoid the 2x as it's soft and reduces light performance to f/5.6. A 1.4x extender could be helpful when you have enough light and want to shoot tighter or from a further distance.

The 200/2.8L II is also a fantastic lens and is much cheaper, but it lacks IS. Same with the 135/2L on a crop cam. Either way, any money saved should go into your tripod to keep things smooth and stable.

Re: EOS vs Full frame compression & Bokeh
 

Thanks, Jon,

we use the Manfrotto tripods with 501 heads which have nice weight/stability and can pan left/right well.

I think I'd hold out for the IS version just because, if I'm going to spend the money, might as well do it right. I've used non-IS lenses and they drive me crazy.

We do use this for weddings. The compression of 200mm is flattering and that's helpful during portrait style moments, but mostly f/2.8 and the reach of 200mm is GREAT during vows/rings - it's the perfect to create a sense of intimacy.

I think we'll get our 2nd 70D and start using them upfront, and move a 5d mark ii for wider rear coverage, and the other 5D mark ii for reaction shots.