Should I sale my 85mm 1.8

kin2son wrote in post #16405092
No. You just aren't using it right.

You don't need to shoot at f11, even f4-5.6 is plenty to accommodate 2 person.

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He could do that with his 28-75, though, so not really any reason to use the 85mm.

Honestly, you just can't reliably shoot two people in the same frame and keep them in focus at large apertures. If that is your goal, you shouldn't be looking at super fast primes.

If you want to blur out the background on a multiple person photo, shoot from far away with a telephoto at like 200-300mm and f5.6 aperture.

ean10775 wrote in post #16405336
Agreed. The distance between your wife's eyes and your child's is at least 8-10 inches I'd guess. At wider apertures and closer camera to subject distances, that's too much variation for both subjects to be in focus.

At f/2.8 and 10 feet the depth of field is about 2" in front and 2" behind the focus point. At f/4 it is about 4" so if you can get the baby's eyes within that distance of your wife's eyes at those apertures, you should be fine.

tkbslc wrote in post #16405353
He could do that with his 28-75, though, so not really any reason to use the 85mm.

Honestly, you just can't reliably shoot two people in the same frame and keep them in focus at large apertures. If that is your goal, you shouldn't be looking at super fast primes.

If you want to blur out the background on a multiple person photo, shoot from far away with a telephoto at like 200-300mm and f5.6 aperture.

this is pretty much the case, unless you shoot from a distance (full body). Great for story telling and subject isolation, but for group shots, you'll have to stop down.

tkbslc wrote in post #16405353
If you want to blur out the background on a multiple person photo, shoot from far away with a telephoto at like 200-300mm and f5.6 aperture.

You can "almost" achieve this effect with the 85 but you will need to stop down to 5.6 or so in order to get all the "eyes" in focus and the background will not be as out of focus when using a 200mm or greater lens. It will also help to isolate your subjects from the background so that the background will be further out of focus.

tkbslc wrote in post #16405353
He could do that with his 28-75, though, so not really any reason to use the 85mm.

I can think of a big one--IMAGE QUALITY. No way is the 28-75 zoom going to come close to the image quality of a prime.

No need in making this more complicated than it has to be. OP, you need to shoot at around F4 to F5.6. To keep the shutter speed up so your image remains sharp, raise your iso up a couple stops as well. iso 400 to 800 should be fine on any canon, modern dslr

If you are going to shoot wide apertures then you need to have both faces in the same focus plane. This shot was wide open with the 85 L II at f/1.2, and I managed to keep both faces sharp. As others have said another option is to stop down. That said, your image still looked good IMO.

brian4646 wrote in post #16405251

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My wife's eyes are sharp. My daughter's is not.

What aperture did you shoot this at?

Basically you need to evaluate the scene and situation then pick the right setting for the job.

As shown above by jrscls, if the couple's faces are on the same plane, using large aperture is fine (however used in cautions with calculated risk). In your example, your daughter's face was in front of your wife and therefore what you should have done was stopping down a lil to have enough dof to accommodate both faces.

As said, it's all about picking the right settings for any given situation, and this comes with experience and time.

Oh also the perceived softness is probably only noticeable when pixel peeping @ 100%. No one will ever notice the softness in 6x4 or 8x10 prints.

I do not disagree with all (or most) of the above advice, but do a focus test of some type with the lens. I struggled with an 85 1.8 (used / Craigslist buy) for a year, finally got ticked and bought a brand new one. Bam - big improvement in focus accuracy. If you need some objective evidence, conduct as objective of a test as you can.....

Sell*

brian4646 wrote in post #16405085
I've been having trouble shooting around f/ 2.2 - 2.8. I shoot my wife and my 1 year old together and have trouble getting them both sharp. I know I could shoot f/ 11 and take care of this but that is not why I purchased this lens. So I started doing the depth of field calculator and found that it would be easier to get more total depth of field with a 35mm lens. I've been saving for the Sigma 35mm. Should I sale my 85mm because of this issue?

You are correct. The long lens makes this very difficult. At the same f-stop max aperture rating a shorter lens will have a much better depth of field. You are shooting at 135mm effective. A 35mm will be much nicer. The 28mm f/1.8 prime would also be good on the crop if you want to get closer.

guitarjeff wrote in post #16406768
I can think of a big one--IMAGE QUALITY. No way is the 28-75 zoom going to come close to the image quality of a prime.

It is at small apertures, where people are advising he shoot.

uOpt wrote in post #16407131
You are correct. The long lens makes this very difficult. At the same f-stop max aperture rating a shorter lens will have a much better depth of field. You are shooting at 135mm effective. A 35mm will be much nicer. The 28mm f/1.8 prime would also be good on the crop if you want to get closer.

lol nicer in what way may I ask?

So by your logic, no one should ever use a 50+mm lens for portrait if you aren't reach limited since shorter focal length give you more dof @ same aperture?

You are mistaken thinking that the 35mm will give you more depth of field. At the same image magnification and the same aperture, the DOF will be the same. Only the background blur will be greater with the 85mm. For example, if you frame a person from the top of their head to the beltline, the DOF will be the same at the same aperture. To get the same image magnification while using your DOF calculator, try comparing a 35mm shot at 3.5 feet to an 85mm shot at 8.5 feet, for example, or 7 feet and 17 feet.

Bearmann wrote in post #16408242
You are mistaken thinking that the 35mm will give you more depth of field. At the same image magnification and the same aperture, the DOF will be the same. Only the background blur will be greater with the 85mm. For example, if you frame a person from the top of their head to the beltline, the DOF will be the same at the same aperture. To get the same image magnification while using your DOF calculator, try comparing a 35mm shot at 3.5 feet to an 85mm shot at 8.5 feet, for example, or 7 feet and 17 feet.

^this.

Same framing, different focal length = same DOF.

As above, you need to get the subject (subjects in this case) in the same focal plane or stop down. So secrets or tricks involved. That is just the way DOF works.

You all are correct. I'll have to think about if I still need the 85mm or just use my Tamron at 75.