f/2.8 vs f/4 DOF samples?

Would anyone be so kind as to provide comparisons of an identical subject with identical framing, one shot at f/2.8 and one at f/4? Preferably longer (70-90mm) focal lengths, and portraits would be great, although any subject is fine.

I want to get an idea of how much shallower the DOF is in real world usage at f/2.8. Thanks

The difference between 2.8 and 4 will be exactly the same as the difference between 4 and 5.6. You can test that with your 24-105 or you 70-200.

Full frame I'm assuming? What lens are you looking at, 70-200?

http://www.the-digital-picture.com …L-IS-USM-Lens-Review.aspx

This is a good comparison at 200mm. Look about 1/4 of the way down the page.

adam8080 wrote in post #16445650
http://www.the-digital-picture.com …L-IS-USM-Lens-Review.aspx

This is a good comparison at 200mm. Look about 1/4 of the way down the page.

Thanks, this is exactly what I was looking for! The site also had similar comparisons made with the 70-200 f/2.8.

This would be full-frame, yes. I've been holding off on purchases as my ultimate lens goal/dream was to replace my f/4 zooms with their f/2.8 Mark II counterparts. That's going to get expensive so I've been saving money. I don't need the extra stop of light, I wanted to get a better look at the DOF comparisons. Debating whether to keep the f/4 zooms and instead add more higher quality primes, or just save for the f/2.8 zooms.

Heya,

Sure, why not. I'll play.

85mm F1.8

I sold my 70-200 f/2.8 IS II for a 85 1.2 and a 135 2.0 a couple of years ago. I realized I only used the 70-200 at 70mm or 200mm and 2.8 wasn't fast enough for me even with the IS.

The 85mm 1.8 is also a great lens at a fraction of the cost.

The Dark Knight wrote in post #16445781
Thanks, this is exactly what I was looking for! The site also had similar comparisons made with the 70-200 f/2.8.

This would be full-frame, yes. I've been holding off on purchases as my ultimate lens goal/dream was to replace my f/4 zooms with their f/2.8 Mark II counterparts. That's going to get expensive so I've been saving money. I don't need the extra stop of light, I wanted to get a better look at the DOF comparisons. Debating whether to keep the f/4 zooms and instead add more higher quality primes, or just save for the f/2.8 zooms.

If you don't need the extra light, get a prime in that range instead.

whmeltonjr wrote in post #16445814
If you don't need the extra light, get a prime in that range instead.

I am certainly leaning that way at this moment. I can keep the two cheapie primes I have, and add the 35mm 1.4 and 85mm 1.8 for less cost than upgrading to the zooms. So that might be another "upgrade" path I pursue.

for what its worth... I've had every iteration of the 70-200 group except the F4 IS, and by far the new 2.8 IS ii version is THE most amazing lens of the group. I know it's costly... but it IS amazing. Both in focus speed and image quality/color.

f/2.8 is not always the same

Check this out:

Horses for courses. I would not be without a 70-200. Occasionally there better options. If you have plenty of dough you can own the best lens for every situation.

Just compare f4 vs F5.6 on your own lenses. The degree of difference will be the same.

It looks like the reason the 200mm prime at f/2.8 looks different from the 70-200mm at 200mm f/2.8 is that the 70-200mm lens at the distance of the samples is not really 200mm. This is usual with zoom lenses, where their focal lengths at closer focus distances is not the specified distance (which is usually at infinity focus).

I guess maybe there are also other reasons for it.

Bookeh is little harsher with 70-200mm f2.8 IS II but one is $2000 and the other is close to $6000. And those are 100% I assume. At say 16x20 print, does it matter that much?

Disclaimer: I may pick 200mm f2 someday.