35mm f2 vs 85mm f1.8

[1000_Islander]

From the OP:

"The main things I like to shoot are newborns, toddlers, children, some senior photos, and engagement photos…… I also take tons of photos of my 16 month old son inside"...................
A fixed 85mm, yes, is a good lens, but it is also restricting indoors; in many rooms you will be backed against a wall to use that 136mm(EQ) lens.

Also, "the IS only works if your object is not moving" is not quite correct. IS is in the lens and it allows the photographer to hold the camera steadier up to about 2 stops. So, convert the stops to a higher shutter speed and we are back to the range of the 85mm.

Don't get me wrong, either the 85mm or 35mm is a fine lens, but just because it is a prime does not make it a better choice. And as I said above, "Good use of flash is much less expensive, and simply shooting in better ambient light will yield better results than any fast lens in poor lighting".

 

[rexbobcat]

From the OP:

"The main things I like to shoot are newborns, toddlers, children, some senior photos, and engagement photos…… I also take tons of photos of my 16 month old son inside"...................
A fixed 85mm, yes, is a good lens, but it is also restricting indoors; in many rooms you will be backed against a wall to use that 136mm(EQ) lens.

Also, "the IS only works if your object is not moving" is not quite correct. IS is in the lens and it allows the photographer to hold the camera steadier up to about 2 stops. So, convert the stops to a higher shutter speed and we are back to the range of the 85mm.

Don't get me wrong, either the 85mm or 35mm is a fine lens, but just because it is a prime does not make it a better choice. And as I said above, "Good use of flash is much less expensive, and simply shooting in better ambient light will yield better results than any fast lens in poor lighting".

Steadier does not mean faster. I can use a tripod with makes the lens as steady as a rock, but I will get blur if I shoot at a slow shutter speed. If you shoot a subject that is moving with IS at 1/100, you will get a lot of motion blur.
If you get a faster lens and shoot at f/1.8 with a shutter speed of 1/400, then there will not be motion blur. These are very obvious photographic concepts.

IS does not make up for a slow shutter speed. And if you literally convert the stops to a higher shutter speed, then the photo will be underexposed because of the smaller aperture.

If the OP is looking for quality over versatility, then the prime lenses at the consumer level are the better choices. However, if she is looking for a lens that she can use in most everyday situations, then the zoom would probably suffice.

Since she wants to go into sports and portraiture, the prime lenses are better because they're fast, small, inexpensive, and have great quality. Since when have you ever seen someone shooting newborns or sports with a 15-85mm?

 

[Buckster]

It's not just about shutter speed and aperture though, and that seems to get lost too often in these conversations about what lenses "can" be used. Use lights, reflectors and ISO to advantage, and many of these so-called lens problems the rivet-counters are keen on arguing over are really of little consequence.

I like the 85mm for portraits, but that's on a full frame camera, and I've got lots of room in my studio. By the way, on the needed shooting length, doorways are a marvelous invention for getting a bit more shooting distance between camera and subject in a pinch - just takes planning ahead.

When I'm in a situation where I can't get the shooting distance because I'm literally up against the wall (I was doing that last night), I just choose a different lens. Last night I used the 24-105mm all night between 50mm and 80mm for portraits of people all gathered for an event/party because my setup space was somewhat limited. My space had no light to speak of, and it would have been florescent anyway, and no matter what, I want to be in control of the light when possible, so "fast" lenses aren't a real issue either. More important is how much aperture I need to get the person(s) in front of me, especially when they want a group of mom, dad, and 4 kids. I used a 2 light setup with an Apollo Orb and another, shallower but large umbrella-box, then dialed aperture, EV and ISO as needed to stay balanced, while sticking with a shutter of 1/160.

I'm composing with the camera. If I do any cropping, it's going to be very little. So, I'm not worried about the relatively small noise increases I might get from working my ISO up and down to balance my aperture.

All this business of supposedly "needing" fast lenses, and the minute differences in sharpness between a prime and a good zoom, etc., differences that even trained eyes have trouble discerning in finished photos, so-called "issues" that seem to hang so many people up, that tend to move the conversation from what to use for shooting portraits in controlled environments to arguing over how that same lens would suck at a soccer game played at night - I'm sorry, but as far as I can tell, it's all just ridiculous tech-banter that means very little if you're a photographer in control of some basic techniques and gear, especially when talking about portraits, where we really are in control.