Wide Aperture Lenses

Somehwere the suggestion came up that when people buy wide aperture lenses they do so to use them at wide apertures. Now looking around I noticed that in relation to the SMC Pentax 50mm f1.2 lens Photo Technique observed something like this (quoted from memory)

Of course apart from black cats in coal cellars there are not many situations where say even f2 is essential, but it does lead to brighter viewing and easier manual focusing.

So what do we think? Do lens purchasers buy wide aperture lenses for using wide open, or is there another reason as well, not necessarily the one postulated by the magazine?

FWIW, I've recently aquired some F2.8 lenses and there superb for portraits and throwing the b/g OOF wide open, plus there great for low light work as well.

A good example is the Sigma 30mm f1.4. There are probably better options for using at normal apertures, but the lens is extremely popular because it opens up low light shooting and, perhaps more importantly, offers a shallow dof combined with good sharpness in the middle of the image. That sort of effect was easy to achieve on a 35mm frame - a 50mm f2 would give just the same sort of look. The crop factor means you have to buy a faster lens to achieve the same effect.

For me, my 50mm f1.7 is stuck on wide open, as is my 35mm f2.4. The nice drift from sharp to out of focus which these lenses provide is what I want. I want parts of the image to stand out more than others.

DA35mm f2.4:




Only occasionally do I want them for their extra sharpness at f8. Actually my Tamron zoom lens probably beats them on sharpness at that setting anyway!

Well I wished I'd had some spare cash floating around for one of the Sigma 70-200 f2.8 zooms that have been for sale on here this week. Super reputation for sports lenses.

I'm also sure John appreciates the advantages of a short f2.8 zoom (16-50, or 24-70 for example) for weddings over and above the likes of the 16-45 f4, for isolating subjects and low light work in church.

I love shooting at f1.8 - f2.2 on my Pentax FA 1.4 and using the HSS on my Metz 50 AF-1 during sunny days.

You can get some remarkable shots.

Taken at f1.8 1/800 HSS on the Metz and a rogue flashbender to direct the light.

http://www.flickr.com/photos/davidbladon/5836492801/meta/in/photostream/

at f2.8 the lens is superb but if you nail one at f1.8 you get that lovely blurry background.

To be honest, I tend to do this

Most of my shooting is around f5.6-f11, going smaller if it would otherwise be too bright or I want motion blur and larger if I need a higher shutter speed to avoid shake.

I still like fast lenses, my DA* 50-135mm being a case in point. It's a constant f2.8 and as a result locks focus very rapidly, the viewfinder is brighter than with a consumer zoom too. I still tend to use it around the f4-f11 range though. It's still sharp at f2.8 but I want more depth of field for most subjects.

I also have the old SMC Pentax 120/2.8 which I'm told was intended to be a flatteringly soft portrait lens wide open, but in a vaguely scientific test it was sharper than my M 135/3.5 at large apertures. Again, I tend to want a bit more depth of field and use it around f8 where it becomes a sharp and relatively tiny telephoto - much like the M 100mm which I know to be very popular.

Interestingly I did meet someone who used f2.8 on a Nikon 70-200mm (ish) with one of their full frame bodies all the time. His attitude seemed to be "I've paid for f2.8 so I'm going to use it" and he thought my habit of stopping down a bit for DoF rather odd! I've also been told that I'm doing it wrong because I'm more interested in aperture and DoF than picking a specific shutter speed (which only becomes important with moving subjects or low light for me).

I often wonder if we in Pentax land are used to Av because it was their only auto mode for many years. The ES was the first to offer it, then the ESII, K2, ME, ME Super, etc but there was no shutter priority mode until the Super A.

Yes Matt, for most things you want a decent depth of field and higher aperture settings tend to flatter less renowned lenses like the 135mm/f3.5, which I also own and rarely use below f5.6. For landscapes I gravitate towards f8 give or take a stop depending on the light. But there are plenty of instances where you want to use DOF as a creative tool and I would have thought the FALtds were natural choices for that sort of photography (if you can afford them :lol

Re the Av thing, I have also always thought in terms of aperture first, shutter speed second - aperture just has a greater bearing on the image than shutter speed, which I usually think of in terms of a limiting factor on aperture rather than a creative tool. My first SLR was all manual, so I can't put it down to Pentax only offering Av mode.

I use fast lenses for two reasons.

1. Creative use of DOF.

2. On the whole the vast majority of lenses only get sharp (or the sweet spot) when stopped down a couple of F-stops. So, the faster the lens, the faster the aperture for that sweet spot. So you could go back to point 1. Fast aperture, shallow DOF, pin sharp! Love it!

I use all my lenses wide open most of the time, just like the small DOF but f/2.8 isn't that extreme fast though, with a faster lens i would probably squeeze it down a little.

I didn't read the Photo Technique review. Were they talking about the fact that the 1:1.2 is relatively soft wide-open?

I use the 1:1.2 for two reasons. First, for portraits, where the wide aperture allows for some stunning results, and the softness doesn't matter.

Second, when the light is very low, and a bit more aperture allows a slightly shorter exposure.

But that won't be necessary with my next camera, the K3.

G

I shoot mostly wide with all my lenses. It's only occasionaly I require a wide DOF.

A shallow DOF gives a pic more depth and msot pics I see shot with a large DEOF where everything is in focus look flat to me ( with the exception of a few landscapes )

I would say I shoot at f/1.2 with my A50/1.2 90% of the time, sometimes stopping down to 1.8 when I want things slightly less dreamy. I have to say it's remarkably sharp at around F/2.0

Similar ethos with my Sigma 30/1.4, which is shot with 1.4 most of the time

Thin DOF (wide-open) is for art. Thick DOF (stopped-down) is for sales.

That said, I cherish my fast lenses, and use my 24/2, 28/2, 35/2, 50/1.2, 85/2, and 135/2.5 wide-open more often than not, varying mainly with light. But I don't need to sell photos. My K50/1.2 certainly isn't for prestige, as nobody around here knows or cares that I have it. And my FA50/1.4 (my only AF prime) sees use mainly as the gotta-get-the-picture lens when its speed and agility are paramount. It's just gravy that it also shoots well stopped-down.

Why buy a fast lens? FOR THE SPEED! Duh... And why buy a slow lens? For the sharpness maybe, but mostly for the lower price. Those German 35-40-50-100 f/4.5's for under US$15 each are sure sweet. But those are for bright days. No good for vampires.

Ahh you mean pictures of products. Yes I can understand that's an area of photography where everything needs to be in focus.

This is interesting, and it was an open question.

For those who think they use their lenses wide open all the time, have a look again at your images. I can think of at least one poster here who says that, but whose images are sharp from foreground to background.

The PT article was a review of the original 50mm f1.2. I have other reviews of that lens which also reveal that it has excellent coma control (no spreading of highlights) and alos 0% decentreing. However, there are better 50mm f1.2 lenses, but nowhere near the price level of the Pentax.

It's an old lens now. And it wasn't so cheap at the time.

G