no nifty fifty for the 4/3 mount?

[kalendae]

usually when my friends buy an dslr with canon or nikon i always recommend the 50mm 1.8 as it is very cheap and makes a world of difference in quality and allows shallow depth of field. Sometimes I feel that really should be the kit lens not the crappy 28-70mm that is the kit lens now. But recently someone had gotten a olympus E510 that uses the 4/3 mount and I again recommended him getting a cheap fast prime lens, but we were not able to find one. Is this the case or are we missing some 3rd party line or such? what do you recommend as a first lens after the kit?

thanks

[inkista]

No, there's really no equivalent to the 50/1.8 for four thirds, yet. The reason 50mm are so prevalent and cheap is that back in the days of film rangefinders and film SLRs, 50mm was normal, and a 50/1.8 or 50/2 was the kit lens you got with the camera. Every SLR lens maker out there has been creating 50mm lenses since the 1930s, and they've had decades to learn how to produce good ones for cheap. Other focal lengths are not so lucky, and wide angle glass is more challenging to design.

Remember that four-thirds has a 2x crop factor. So a "normal" lens for four-thirds is quite a bit wider than 50mm; in essence, you're looking for a 25mm lens, which is just flat out going to be more expensive than a 50mm.

The two options for four-thirds are usually the Olympus 25 f/2.8 pancake ($225), or the Panasonic 25 f/1.4 (designed by Leica and about $1000). You can get an OM-mount adapter ring for four-thirds, and hunt up an old manual focus Olympus OM-mount Zuiko 50mm f/1.8 for about $20-40 on the used market. But its FoV is equivalent to a 100mm lens, and it's more like a short telephoto, and of course, you don't have autofocus or the ability to shoot in any modes by Manual and Aperture Priority.

I'd say your friend's best bet is the 25mm f/2.8 pancake.

It's a complete shame that Olympus is so sparse of fast affordable primes, given how the OM system was rife with them. The problem with going for an OM lens, though, is that you're forced to hit the used market, and you never know what condition the lens is in. AND you're fighting all the crazy Canon shooters who use them with adapter rings.

[Slushie]

Originally Posted by inkista

I'd say your friend's best bet is the 25mm f/2.8 pancake.

It's a complete shame that Olympus is so sparse of fast affordable primes, given how the OM system was rife with them. The problem with going for an OM lens, though, is that you're forced to hit the used market, and you never know what condition the lens is in. AND you're fighting all the crazy Canon shooters who use them with adapter rings.

I agree!!! Olympus hasn't got anything close to the "nifty fifty" where the $$$ is affordable...

Hunting down an older used lens has been hard and I eventually saved up enough to pick up both the Leica/Panasonic 25mm F1.4 and the Oly 50mm F2.0. Both are VERY good lens but also VERY VERY VERY expensive making them not so nifty. The 25mm is also extremely difficult to find in stock.

Having said that... if they ever do get their hands on one, these two lenses are super nice to work with.

[Doug Pardee]

Originally Posted by inkista

The reason 50mm are so prevalent and cheap is that back in the days of film rangefinders and film SLRs, 50mm was normal, and a 50/1.8 or 50/2 was the kit lens you got with the camera. Every SLR lens maker out there has been creating 50mm lenses since the 1930s, and they've had decades to learn how to produce good ones for cheap.

To add to the above:

Most 35mm SLRs had flange-to-film distances of 40-45mm or so. A 50mm lens could be produced that sat effectively 50mm from the film. That meant that the lens could be built as a simple Gaussian design, without any telephoto or retrofocal lens groups that would complicate the lens, increase the cost, and reduce the image quality.

With the 4/3 system, the flange-to-sensor distance is still about 39mm. A "normal" lens of around 25mm needs a fairly powerful retrofocal lens group to get it to focus 39mm away. That retrofocal group raises the cost and reduces the image quality.

As for 50mm lenses specifically, the other manufacturers chose to make their DSLRs compatible with their older lenses. Olympus chose to design an entirely new lens mount and series of digital lenses, so there aren't any old 50mm 4/3 lenses hanging around from the film days.

One of the features of micro-4/3 is a reduced flange-to-sensor distance of a bit over 19mm. It should be possible to make a 25mm "normal" lens with a simple Gaussian design for micro-4/3. It seems that nobody has chosen to do so (yet).

[inkista]

Cool beans. That tech info just clicked a lot of things into place in my head.

Originally Posted by Doug Pardee

...One of the features of micro-4/3 is a reduced flange-to-sensor distance of a bit over 19mm. It should be possible to make a 25mm "normal" lens with a simple Gaussian design for micro-4/3. It seems that nobody has chosen to do so (yet).

Panasonic keeps saying they're going to come out with that 20mm f/1.7 pancake... (sigh).... I do wonder if the Oly 17mm f/2.8 pancake is built along those lines.

Interesting, though, that four-third's flange distance is 38.67 mm, which might explain why making a cheap normal may be impossible for the format. A simple design could only be achieved at around 40mm, and that's too long to be normal. Also explains why they chose the flange distance they did for micro four-thirds.

[Doug Pardee]

Originally Posted by inkista

Also explains why they chose the flange distance they did for micro four-thirds.

The large flange-back distance for 4/3 was mainly because it was decided to require that all 4/3 lenses be telecentric (in the image space), which means that the light coming out of the back of the lens is coming straight out, not fanning out in a conical shape. Telecentricity eliminates the problem of the sensor elements at the edges and corners having to deal with inefficient photon capture due to light coming in on a slant. The longer flange-back distance makes it the easier to make telecentric lenses.

Because the flange-back distance is unusually large compared with the sensor size, there's room to swing the mirrors sideways instead of upward and Olympus did that. Other than making for some unusual camera shapes, I don't know what advantage they reaped from that.

With the micro-4/3 system, lenses are not required to be telecentric. The flange-back distance is mainly limited by needing enough room for non-telecentric lenses to get a decent amount of light into the corners and edges, and of course leaving room for the shutter mechanism and all of the stuff stuck on the front of the sensor.

[inkista]

... which also explains why the image engines for micro four-thirds are doing in-camera correction of vignetting, CA, and distortion. You are teaching me so much today! Thank you!

The telecentric issue is also why I'm skeptical every time I hear someone pronouncing that Leica's going to come out with a full-frame M, given the technical hoops they had to jump through via offset microlenses to overcome that problem for a 1.3x crop sensor and a 28mm flange-to-sensor distance.

[Slushie]

@ Doug

ooooh.... that makes so much stuff make so much more sense to me now! Until now, I just though a mm here or there was just that... as for mirrors swinging sideways... that was the e-300?

also... if I understand some of what you're saying as well, does that mean that theoretically, the u4/3rds mount might be able to use pretty much any lens out there (if the appropriate adapter were made for it)?

[kalendae]

yeah thanks for the great indepth explanations and thanks for the recommendations. The pancake is very cool!

[inkista]

Originally Posted by Slushie

...does that mean that theoretically, the u4/3rds mount might be able to use pretty much any lens out there (if the appropriate adapter were made for it)?

You have no idea. I've already seen folks posting pics of adapting Olympus Pen F, M39 (Leica thread mount), Canon FD, Leica M, and there's talk of a Contax G adapter (it's an autofocus system, so getting focus control is the big problem). One of the main appeals of µ4/3 for vintage lens geeks is the fact that it can take all the SLR lenses, as well as rangefinder glass. If you do a search on eBay for adapters to micro four-thirds you'll see a fairly staggering array.