[johnmflores]

I never really got along with 50mm on APS-C. The crop factor made it too long for indoors yet too short for outdoors.

And even if Canon and Nikon have fast 1.4 and 1.8s, aren't we gaining the stops back with in body image stabilization?

[Biro]

I never really got along with 50mm on APS-C. The crop factor made it too long for indoors yet too short for outdoors.

And even if Canon and Nikon have fast 1.4 and 1.8s, aren't we gaining the stops back with in body image stabilization?

The image stabilization point is exactly the excuse many camera makers have been using for a while. To an extent, they are correct. But while IS can compensate for the photographer's movements, it doesn't compensate for a subject's movements - nor does it offer the same DOF effects on f/2.8 and slower lenses as one would get at f/1.4. Frankly, I'd be happy with a fast, sharp prime from Pentax anywhere in the 28-35mm range. By fast, I mean faster than f/2. My frustration continues to grow. I'd prefer not to have to default to Sigma. But if I do, I won't be interested in buying a similar Pentax lens later.

[stevebrot]

I have a copy of "The Amateur Photographer's Handbook", published in the 70s I believe. The author reports as a matter of fact that "fast" lenses start at f/2.8. So calling f/2 fast isn't something new.

That is my understanding as well and is particularly true if you consider the full gamut of camera formats. I regularly shoot with f/2 glass and seldom feel the need for the additional stop to f/1.4 unless I want less DOF. To be truthful, I can't imagine trying to shoot something like a wedding at even f/2...unless, of course, you want all of your shots to be soft.

Steve

[stevebrot]

Are we becoming too obsessed with having a faster lens?
How fast is fast enough?... 'Just a little faster than what I have', I guess...

But what useable DOF can we get from a lens of f/2 or larger, esp. in the >50mm variety?
Do we want them faster just so that we can have the choice to go faster when we want? Or brag that 'my lens is faster than your lens', because size matters?

When the new 85/1.0 comes out, there will be those who won't be satisfied until a 200/1.2 is available... and so on and so forth...

I think we really like the "bigness" of fast lenses. That front element is usually pretty impressive. Sort of like having a cigar boat or a long sports car. Compensation, ya know...

Steve

(Really like the huge front element of my Jupiter-9...)

[stevebrot]

...I appreciate the faster lenses definitely making viewfinders brighter in camera...

That is the other dirty little secret...

On my K10D with the stock screen, the viewfinder brightness is about the same at f/3.5 as it is at f/1.7. Ditto for the apparent DOF. Using a fast manual focus lens with the stock screen is pretty much a recipe for OOF pictures when shooting wide-open.

Steve

(Didn't start getting sharp pictures with my faster manual focus lenses until I got a Katz Eye screen...)

[rparmar]

Sure f/4 is fine at that FL - would f/1.4 be all that more useful in terms of DOF control?

I appreciate the faster lenses definitely making viewfinders brighter in camera and providing swifter AF in low light, but composition? How do you mean, Robin?

I just posted some comparison shots at f/2, f/2.8 and f/4 over in the thread Testing the Vivitar 28mm K01 by taking kitten photos. These are maybe not the world's best to illustrate my point, but I do like the flexibility I get in getting to compose in 3D at f/2 as opposed to the more "normative" image at f/4. If I had f/1.4 it would help when the subject was not so close to the lens but I still wanted to isolate it from the background.

Of course there is also the IQ factor. Given that a lens needs to be stopped down once or twice to become truly sharp, an f/1.4 means a usable f/2 whereas an f/2 means a usable f/2.8.

[Charles Hueter]

Are we becoming too obsessed with having a faster lens?
How fast is fast enough?... 'Just a little faster than what I have', I guess...

But what useable DOF can we get from a lens of f/2 or larger, esp. in the >50mm variety?
Do we want them faster just so that we can have the choice to go faster when we want? Or brag that 'my lens is faster than your lens', because size matters?

When the new 85/1.0 comes out, there will be those who won't be satisfied until a 200/1.2 is available... and so on and so forth...

I don't see any need to speculate on or hint at less-than-honorable motives.

I have a K100D and a K20D. When I bump against my comfort level with high-ISO digital noise and am bracing myself against a wall or a counter even with SR engaged, I really appreciate those extra partial stops.

I want an A 50/1.2 because in my experience shooting indoors during parties and clubs, going from 1/4th a second to 1/8th or from 1/10th a second to 1/15th a second can make a big difference if you time the shot right.

Then there's the extra reach you get with a flash shot on a very fast lens.

[Aristophanes]

I don't see any need to speculate on or hint at less-than-honorable motives.

I have a K100D and a K20D. When I bump against my comfort level with high-ISO digital noise and am bracing myself against a wall or a counter even with SR engaged, I really appreciate those extra partial stops.

I want an A 50/1.2 because in my experience shooting indoors during parties and clubs, going from 1/4th a second to 1/8th or from 1/10th a second to 1/15th a second can make a big difference if you time the shot right.
.

That's the part I don't get.

What you want is higher ISO with less noise.

What you're getting with faster lenses is actually less resolution because your DOF is so shallow all but a person's tip of their nose is OOF. That's a very shallow perspective, and in the aesthetics of photography, a very limiting technique, unless you want all your shots to look very similar, (and similar to everyone else), with a lot of softness on the edges.

Stops is not the same thing as aperture. What you give up going from f/2.8 to f/1.2 is perspective. You don't get that "speed" without giving something up visually. A 50/1.2 at 10 feet gives you what? 7 inches of DOF? Might work for an MRI, but you'll see a lot of beer bottles in focus and no faces as they raise a toast to the photographer. We like to see faces with clarity. There's artistic exceptions, of course, but for "street" photography or "scene" shots with people as the subject, we like DOF to capture the person.

The FA 31 at f/1.8 with a respectful 10 feet distance between photographer and subject has a DOF of about 2.27 feet, ideal for getting the portrait without losing the parts. (Ears, people, ears! How many times have I seen a bragging "fast glass" photo where the subject's ears so far OOF they look like they've been painted on. It's one thing to have a hand from a dancer blurred as we expect hands to move, but ears?!), but still offering superior bokeh and sharpness—the aesthetic balance. The DA 35 at the same distance at f/2.8 is just a shade longer.

There's a method to the madness.

[Russell-Evans]

Yes, anytime I have to compose in dim light the half stop makes a huge difference.

It's a doubled sword though isn't it? The thinner the DOF, the harder it is going to be to get a correct focus, personal skill aside.

Thank you
Russell

[Charles Hueter]

That's the part I don't get.

What you want is higher ISO with less noise.

No, one way of getting what I want is better image quality at higher sensitivities. I would love to dial in 3200 or 6400 ISO without worrying over noise. However, it seems the only way that is going to happen is with a very expensive, system-crossing upgrade. I've got my hands full with the K-mount.

Incidentally, I don't spend all of my time in underground clubs lit with a single 40W bulb. If that's all that mattered to me, I probably would have a 5D and the 50/1.2 by now. But crappy lighting is something I encounter often enough that I keep my eye out for good deals on fast lenses.

What you're getting with faster lenses is actually less resolution because your DOF is so shallow all but a person's tip of their nose is OOF. That's a very shallow perspective, and in the aesthetics of photography, a very limiting technique, unless you want all your shots to look very similar, (and similar to everyone else), with a lot of softness on the edges.

I'm fully aware of this. My first lenses were M42s mounted to the K100D. Weak viewfinder + hazy 50/1.4 = steep learning curve. I learned to accept a certain number of missed shots due to focus errors. My point - which no one else is required to share - is that I'd rather deal with focus problems than hopelessly slow shutter speeds. Also, since most of these shots are for informal friend consumption, I don't really care if I'm pulling the best detail out of the scene...I just want the shot. My preferences push me away from 3200+ ISOs because getting rid of the noise to my satisfaction is annoying enough to aim for another solution.

Stops is not the same thing as aperture. What you give up going from f/2.8 to f/1.2 is perspective.

If I'm getting 1/8th of second at 1600 ISO on a lens set to 1.7, I'm not even going to bother with a lens that maxes out at 2.8.

My F 50/1.7 (my current fastest lens) gives me the same perspective as a future A 50/1.2 will. Fewer things will be in focus, but we're already talking about thin DOF in these situations anyway.

50mm @ 1.7 shot at 10 feet = 0.81 feet of DOF
50mm @ 1.2 shot at 10 feet = 0.57 feet of DOF

In these situations, I've already given up on autofocus unless I'm lucky and the subject moves into brighter light for a moment. It isn't about blurring the foreground or the background for me. It's about getting close to a reasonable shutter speed without having to spend additional time dealing with noise reduction.

[Ash]

Point made Charles, but I find it hard to appreciate any meaningful reduction in noise between shooting at f/1.7 and f/1.2 (less than a stop difference), given that you're maxing out on 'handholdable' shutter speeds.

It'll be the difference between an ISO 1600 and 2500 shot - if exposed correctly, both with still give reasonable detail with acceptable noise - but the difference between them?

I'd take my hat off to you for the low-light portraits you take at f/1.2 that come out sharp.

[Charles Hueter]

It'll be the difference between an ISO 1600 and 2500 shot - if exposed correctly, both with still give reasonable detail with acceptable noise - but the difference between them?

Unfortunately, the K100D only does full ISO stops and I really hesitate to take color pictures on the K20D above 2200. I dislike the noise patterns that develop. My preference is to stay at or below 1600 for both.

I'd take my hat off to you for the low-light portraits you take at f/1.2 that come out sharp.

They aren't always portraits.

Sometimes I just see something that looks nifty.



Ironically in this case, it was something I shot at 3200 ISO.

[NaClH2O]

The 28mm 1.8 is a nice lens, but the samples I've seen of the 30mm suffered badly from the characteristic Sigma yellow cast. I hate that. 24mm would be just about ideal for a normal lens, but I'm not familiar with it. Reviews I've seen have been mixed.

My only problem with it is that it's on the large side. But decent IQ, good color rendition, good close focus. Excellent low light lens. I don't use it as often as I should.

NaCl(it's a good focal length for me)H2O

[rparmar]

My F 50/1.7 (my current fastest lens) gives me the same perspective as a future A 50/1.2 will.

Also, the 1.2 will let you shoot at 1.7 with better image quality than the F50, if I'm remembering my acuity figures correctly.

By the way there were two K50/1.2 lenses up for sale on the forum recently. That's a much cheaper way to get the same results. I have one myself.

[Ash]

Unfortunately, the K100D only does full ISO stops and I really hesitate to take color pictures on the K20D above 2200. I dislike the noise patterns that develop. My preference is to stay at or below 1600 for both.

They aren't always portraits.

Sometimes I just see something that looks nifty.

Ironically in this case, it was something I shot at 3200 ISO.

Indeed you've proven here, as well as quite a few other users, that ISO 3200 is useable!