CANON 85 f/1.8 vs 100 f/2 and depth of field

I searched but couldn't find anything and I also looked at the Online Depth of Field calculator but couldn't figure it out for the answer I'm looking for - Which one of the above mentioned lenses would give me more background blur if the subject is framed the same (not shot from the same distance) and both lenses are used wide open?

pixel_junkie wrote in post #9761895
I searched but couldn't find anything and I also looked at the Online Depth of Field calculator but couldn't figure it out for the answer I'm looking for - Which one of the above mentioned lenses would give me more background blur if the subject is framed the same (not shot from the same distance) and both lenses are used wide open?

you wont notice any difference but what i can tell you is that the 85 is not very sharp wide open and is prone to CA wide open - at least the one I had was - FWIW

Thank you. I had 2 85s, one of them was sharper. Lots of CA with both, you're right. Now I have the 100 f/2 which to me, in terms of performance, is 99% a 135L. But was curious about the DOF, since one of them is faster and the other longer.

I think if they're framed the same, the 85mm f/1.8 should give you a bit less depth of field and more background blur.

the 135 will give the best background blur

https://photography-on-the.net …hp?p=9397509&po​stcount=26

They look pretty much the same. The 85/1.8 might be a smidgen bigger...but who's gonna notice in an actual picture?

I had a 85 in hand,
what i can say is the wide open is sharp.
only the ever 1 downside of this lens is the CA and LoCA is a disaster

I know the 85 is a popular lens, but the excessive purple fringing is a deal breaker for me. It does make a good indoor sports lens on a crop body.

Wide open, they're about the same. But, as mentioned already, you'll get some CA at 1.8 with the 85mm. Because of this, I purchased the 100mm 2.0. My favorite trait of the 100mm is its outstanding background blur. Its a very underrated lens.

toxic wrote in post #9765627
https://photography-on-the.net …hp?p=9397509&po​stcount=26

They look pretty much the same. The 85/1.8 might be a smidgen bigger...but who's gonna notice in an actual picture?

the distance to subject tends to be greater with 135 so that helps with the bokeh

No bokeh like the 85 f1.2 though but that doesnt focus fast enough to catcha tortoise

Couple thoughts on my 85mm f/1.8. I usually shoot with it at 2.0. The CA (purple fringing) happens a lot, but not when (on rare occasions) the exposure is perfect. As far as BG, here's a good example of what it looks like at high ISO, f/2 and probably 1/640 on the shutter:

pixel_junkie wrote in post #9761895
I searched but couldn't find anything and I also looked at the Online Depth of Field calculator but couldn't figure it out for the answer I'm looking for - Which one of the above mentioned lenses would give me more background blur if the subject is framed the same (not shot from the same distance) and both lenses are used wide open?

With the same framing, the 85 1.8 will have a slightly shallower DOF.

Sensor Size: Full Frame
Focal Length: 85mm
Aperture: f/1.8
Subject Distance: 8.5ft
Total DOF: 0.32ft

Sensor Size: Full Frame
Focal Length: 100mm
Aperture: f/2.0
Subject Distance: 10ft
Total DOF: 0.35ft

The 85 will have slightly shallower DOF when both are wide open, but the 100 will show probably a tiny bit more background blur (due to the narrower AOV).

135@f2

BenJohnson wrote in post #9766595
With the same framing, the 85 1.8 will have a slightly shallower DOF.

Sensor Size: Full Frame
Focal Length: 85mm
Aperture: f/1.8
Subject Distance: 8.5ft
Total DOF: 0.32ft

Sensor Size: Full Frame
Focal Length: 100mm
Aperture: f/2.0
Subject Distance: 10ft
Total DOF: 0.35ft

I love math. +1