Micro 4/3 Lens FAQ

Micro 4/3

This FAQ is divided into several sections, based upon topic. It’s fairly long, so if you have a specific question, your best bet is to search for a specific term or phrase. The sections are:

  • General – micro 4/3 lenses and some general photographic advice
  • Autofocus – comments regarding autofocus speed and lack thereof
  • Image stabilization – where stabilization is available, and where to use it
  • Classic 4/3 lenses – lenses built for 4/3 (not micro 4/3) bodies
  • Adapted lenses – lenses built for other systems
  • Lens issues – specific issues with particular lens and lens/body combinations

General Lens Questions

What lenses are made for micro 4/3 cameras?

There is currently a large selection of micro 4/3 lenses available. Please see the lens chart for a listing of all current models and basic specifications.

What are the best micro 4/3 lenses?

This depends entirely on what you are photographing. I do have some recommendations, but remember that lens evaluation is a very subjective art – what appeals to me may not appeal to you!

What are equivalent focal lengths? What is ‘crop factor’?

To compare focal lengths between micro 4/3 and 135 format film or full frame digital cameras, you multiple by 2 (and divide for the reverse comparison). In other words, a 25mm lens on a micro 4/3 camera produces similar framing to a 50mm lens on a full frame camera. 2 is often referred to as the crop factor because if you double the length of the diagonal of a 4/3 format sensor you get something roughly the size of a full-frame sensor.

How about f-stops? Do you also multiply by the crop factor to compare apertures?

Sort of. In terms of light gathering (metering), an f/1.4 lens on one format is the same as on another format. So there’s no conversion there. In terms of matching appearance, you do multiply by 2 to get the same depth-of-field, if you’ve got equivalent framing. In other words, a 25mm f/1.4 lens on a micro 4/3 camera produces the same framing and depth of field as a 50mm f/2.8 lens on a full frame one. Note that a 25mm f/1.4 lens on full frame would have the same depth of field, but offer a much wider angle-of-view.

What aperture do lenses perform best at on micro 4/3?

Most lenses (and micro 4/3 ones are no exception) perform best closed down around 1.5-2 f-stops from their maximum aperture. So if you have a lens with a max. aperture of f/3.5, it will most likely be sharpest between f/5.6 and f/7.1. That said, lenses do vary and if you are picky, it’s best to test yourself, or look at lens test results from a site like photozone.

What is diffraction? When do it occur?

Diffraction is generally used to refer to a softening that occurs at smaller apertures. In practice, stopping down to f/11 and beyond results in significantly less sharp images on m4/3. A smaller degradation can be seen from f/8 to f/11, although with lower quality lenses, it may not be visible. The exact point where this happens depends on the size of the pixels on the sensor (it occurs earlier with smaller pixels).

What is the best aperture to use on micro 4/3 cameras?

It depends. The first concern should always be depth-of-field – is the correct part of the image in focus? It is ideal to shoot at a lens’s sharpest aperture, but this isn’t always possible. At the other end, it is also best to avoid smaller apertures and the loss of image quality to diffraction. Do bear in mind though that both diffraction and lens sharpness are in reference to the pixel level of the image – something you simply won’t see if you’re not viewing the image at 100% on your screen or printing very large.

Can I use my Panasonic lens on my Olympus body (or vice versa).

Yes. Any micro 4/3 lens can be used on any micro 4/3 body. You may freely mix and match among manufacturers and basic features work the same.

What is focus-by-wire? When will I use it?

Focus-by-wire means that the focusing ring on the lens is not directly connected to the focusing mechanism of the lens. Instead it connects electronically to the lenses’s focusing motor. All micro 4/3 lenses use focus-by-wire except those without autofocus motors. If you use manual focus with micro 4/3 lenses (or most 4/3 ones), you’ll use focus-by-wire. The main advantage is that it allows finer-control over focus adjustments. The downside is that it makes presetting the focus distance quite difficult. Olympus has a feature called ‘Snap Focus’ on some of their lenses which more or less avoids these problems.

What is ‘focus peaking’? Does micro 4/3 offer it?

Focus peaking is a technology developed by Sony where the areas of highest contrast are highlighted. It can be a great aid for manual focusing. The latest generation of Olympus and Panasonic cameras offer it (the Olympus E-P5, E-M1 and E-M10 and the Panasonic GM1, GF6, GX7 and GH3). Older models do not support it.

Is there any disadvantage to mixing and matching micro 4/3 lenses and body makes (e.g. Olympus body with Panasonic lens)?

In general, no. In most respects, the lenses behave the same regardless of the body used. Autofocus, aperture control and automatic correction of geometric distortion work the same across all combinations. The only real differences come when using Panasonic lenses on Olympus bodies (vs. on Panasonic bodies). They are:

  • Panasonic bodies correct lateral chromatic aberration on Panasonic lenses. The current generation of Olympus bodies (E-M1, E-M10) correct lateral CA on Olympus lenses, but older Olympus bodies do not..
  • OIS (optical image stabilization) on lenses that do not have a physical OIS switch can’t be enabled on Olympus bodies older than the E-PL5.

What is a polarizer? Is there a particular kind I need for micro 4/3 cameras?

A polarizer blocks light that blocks light of a particular orientation. It is often used to prevent reflections (in water for example) and darken skies (landscapes). There are two types of polarizers – circular and linear. Micro 4/3 works with either one (DSLRs don’t work with linear polarizers).


Why does my lens focus so slowly?

With autofocusing, there are two variables, the camera, and the lens. There are a couple of lenses that are well known for slow autofocus performance: the Olympus 14-42/3.5-5.6 mk1, the Olympus 17/2.8, the Panasonic 20/1.7. These lenses feature designs that simply aren’t conducive to fast focusing (the 14-42mk1 had a rotating front element, and the 20/1.7 requires the entire lens to move forward are backward when focusing).

Generally though, autofocus speed is limited by the camera. This is particularly true with the first and second generation m4/3 bodies – the Olympus E-P1, E-P2, E-PL1, E-PL2 and Panasonic G1, GF1, GH1, G2, GF2 and G10. More recent bodies are generally pretty good when it comes to focusing on a particular (usually stationary) object (S-AF), but still don’t do very well with tracking autofocus (C-AF), where the camera must predict the motion of an object as it moves. To be fair, no camera is perfect at C-AF, but because of the way the contrast-detect based autofocus (CDAF) works, micro 4/3 is at a particular disadvantage. The one exception so far is the Olympus E-M1 which has phase detection built into the sensor, and has quite decent C-AF performance.

Image Stabilization

Is there any reason not to leave image stabilization on all the time?

Yes. While generally very useful, stabilization can degrade your images under certain situations:

  • Stabilization should almost always be disabled if the camera is ona tripod.
  • At high shutter speeds, stabilization may introduce a small amount of blurring. As a rule of thumb, if the shutter speed is more than twice the focal length of the lens, I would disable stabilization.

I have an Olympus body and a Panasonic lens that supports OIS. Can I turn on both stabilization in the body (IBIS – in-body image stabilization) and in the lens for even better stabilization?

You shouldn’t. The systems operate independently and as such can interfere and actually generate vibrations, rather than reducing them. On bodies newer than the E-M5, the camera will automatically disable IBIS if OIS is enabled. On older bodies, make sure to only enable one.

Which type of image stabilization is better – in-camera (IBIS) or in-lens (OIS)?

There’s not really a general answer. The effectiveness of IBIS and OIS depends heavily on the specific body and lens. Overall from what I’ve seen, on the Olympus E-M5, the IBIS is usually better, and on the older models, OIS is better on longer focal lengths (150mm+) and IBIS on shorter focal lengths.

I have an Olympus body and a Panasonic lens with OIS. How do I enable OIS?

Cameras older than the E-PL5 do not know anything about OIS. As such, to enable OIS, you have to use the switch on the lens. If the lens does not have a switch (for example on the Panasonic 14-42mm f/3.5-5.6), you can’t enable OIS on it. Do not enable IS in the camera at the same time – the two will actually conflict, causing less sharp images.

With the E-PL5 and newer, the camera can communicate and set the OIS state in the lens. To enable OIS, you must first enable IS in the camera – change the IS setting to S-IS1 (or S-IS2 or S-IS3). Next, you should go to the Custom menu (the Wrench) and in section C, set ‘Lens I.S. Priority’ to On. At this point the camera will use OIS if the lens supports it. Note that if the lens has an OIS switch and you switch it to on, OIS will be used regardless of the ‘Lens I.S. Priority’ section.

Even though I’ve turned OIS off, I can still hear the stabilization motor working. Is this normal?

Yes. The lens elements used for stabilization are essentially free-floating, so the motor must operate to keep them from moving around. If you turn off the camera and turn it over, you may be able to hear a ‘clicking’ sound as the free elements shift.

I’m seeing blurred images at shutter speeds that should be sufficient for sharp images. What’s going on?

There’s recently been a spate of reports of people with precisely this problem – especially for images taken using relatively lightweight lenses and shutter speeds in between 1/60 and 1/250. The problem appears to largely be the result of vibration caused by the motion of the shutter opening, or shutter-induced shock (shutter shock) as it is usually called. Due to a lack of mass, this vibration is not damped and consequently the camera moves slightly while the image is being recorded. Certain camera’s shutters also seem to be more prone to this (e.g. the E-P5).

There are two general solutions. One is to use the delayed shutter mode that Olympus calls anti-shock. By inserting a time delay between the opening of the shutter and the start of image capture, the motion has time to die down. A setting of 1/8s appears to be sufficient to cure the problem in most cases. The second option is to use the electronic ‘shutter’ available on certain Panasonic bodies. Here the camera does not use the focal plane shutter at all, hence no vibration. Unfortunately, because the sensor is not read out all at once, using the electronic shutter means you may get distortion of moving objects in your image.

Classic (non-micro) 4/3 Lenses

Can I use 4/3 (non-micro) lenses on my micro 4/3 body?

Yes. You will need a micro-4/3 to 4/3 adapter, and some functionality will be compromised.

Is there a difference between the various 4/3 adapters?

Functionally, no. You will not gain any functionality such as faster autofocus or better compatibility by going with one adapter model over another. The build quality of the original Panasonic and Olympus adapters seems to be a bit more solid than the newer ones. The one functional difference is that the Olympus MMF-3 adapter has gaskets for weather-sealing. If you have a sealed lens, and a sealed body, that may be an attraction. Current adapter options include:

  • Panasonic DMW-MA1 – the first adapter released
  • Olympus MMF-1 – seemingly discontinued
  • Olympus MMF-2 – less solid construction than the MMF-1
  • Olympus MMF-3 – like the MMF-2 but with two rubber sealing rings, the most expensive by a fair margin
  • Viltrox JY-43F – a third party clone available currently only on eBay, and the least expensive of the lot

What are the drawbacks to using 4/3 lenses on micro 4/3 bodies?

In a word – autofocus. Speed and to a lesser degree accuracy are considerably worse than with native micro 4/3 lenses. Moreover, autofocus is limited to single – there is no tracking or continuous AF ability with these lenses. In terms of speed, there are two classes of 4/3 lenses – those optimized for CDAF (contrast detect autofocus) which take generally 1-2 seconds to AF, and those not optimized for CDAF, which take anywhere from 2-6 seconds.

4/3 lenses that aren’t optimized for CDAF will not autofocus at all on the first generation of Panasonic bodies, the G1, GF1 and GH1. Also, newer bodies (e.g. G3, GH2, E-P3 and E-M5) autofocus a fair amount faster with 4/3 lenses than old ones do (E-P1, E-P2).

Beyond autofocus, there’s also the fact most 4/3 lenses are fairly large, and may not handle comfortably with the smaller micro 4/3 bodies.

Note that Olympus’s newest E-M1 model includes phase detection sensors, allowing 4/3 lenses to be focused without using CDAF. E-M1 autofocus performance with 4/3 lenses thus has none of the disadvantages mentioned above – speed is about the same as on the cameras the lenses were designed for, and tracking autofocus is possible (and works fairly well). The only real limitations are that the AF sensors only work well when their is vertical contrast, so focusing on horizontal lines or in low light can be difficult.

Which 4/3 lenses are optimized for CDAF?

    • Olympus ZD 9-18mm f/4-5.6
    • Olympus ZD 14-42mm f/3.5-5.6
    • Olympus ZD 14-54mm f/2.8-3.5 II
    • Olympus ZD 40-150mm f/4.0-5.6
    • Olympus ZD 70-300mm f/4.5-5.6
    • Olympus ZD 25mm f/2.8
    • Panasonic Leica D Vario Elmar 14-50mm f/3.8-5.6
    • Panasonic Leica D Vario Elmar 14-150mm f/3.5-5.6
    • Panasonic Leica D 25mm f/1.4

Adapted (Legacy) Lenses

Can I use my Nikon/Canon/Sonya/Pentax lenses on my micro 4/3 camera?

Yes. Virtually any type of lens can be used on micro 4/3 bodies with an adapter. There are a couple of things to keep in mind:

There is no autofocus. Focus is purely manual. Older lenses tend to have better focusing rings, and thus are better candidates for adapting. Focus by wire lenses are essentially useless.

Aperture is controlled on the lens, not the body. So in terms of shooting mode, you’re generally limited to manual and aperture priority. As a corollary, lenses where the aperture is controlled electronically are a problem as there is no way to set the aperture from the body. Lenses with an aperture ring are best for adapting.

What adapter should I use for my adapted lens?

Most adapters are ‘dumb’ spacers – they have no electronics and their purpose is to ensure that the lens is the correct distance from the sensor. These are fine for lenses with aperture rings.

For lenses that don’t have aperture rings such as Nikon’s G lenses, you’ll need an adapter that lets you control the aperture.

The Canon EF mount is special, as the aperture is controlled electronically. You either have the option of always using the lens at a preset aperture (set by putting the lens on a Canon camera) or buying an adapter with a built-in aperture (not very precise control), or a smart adapter that lets you set the aperture directly (expensive).

While there are several vendors selling high-priced adapters, for most lenses, especially those with built-in aperture rings, an inexpensive adapter off of eBay is more than good enough.

What are the compromises involved in using adapted lenses?

First, as noted above, you lose autofocus. There are various methods for focusing manually, but it is not as convenient nor as fast as modern autofocus. The lack of focus peaking makes it a bit hard as well.

In terms of image quality most older lenses are designed for film, which is significantly less demanding than a digital sensor with small pixels like micro 4/3. As a result, image sharpness is generally not as good as with modern lenses. Very old lenses are not coated or multicoated, meaning they tend to be lower contrast and not deal well with light sources inside the image frame.

Due to the crop factor, adapted lenses also serve different purposes than initially intended. For example, a 24mm lens on 135 format film gives a wide-angle perspective, whereas on micro 4/3 it gives a normal one. There are in fact very few adapted lenses that offer a wide-angle perspective on micro 4/3.

What is a Speed Booster/Focal Reducer/Lens Turbo?

Speed Booster is actually the (trademarked) name for Metabones’ lineup of focal reducers. There are actually a number of different focal reducer designs available from Metabones as well. A focal reducer essentially does the opposite of what a teleconverter does, concentrating the image project by the lens onto a smaller area. This has two primary effects – first the effective focal length of the lens is decreased – which is particularly helpful when looking at wide-angle lenses. The second result is that by taking the same amount of light but projecting it over a smaller area, you are essentially increasing the brightness of the lens, i.e. its f-number.

Because the focal reducer essentially shrinks the image circle, to ensure that the image covers the entire camera sensor, they only make sense with lenses designed for larger formats. As a result, all current focal reducers are essentially designed as adapters for 135 format lenses. Most designs right now are 0.7x focal reducers, meaning the lenses they adapt effectively have their focal length multiplied by 0.7 and their aperture increased by 1 stop. A 50mm f/1.8 lens thus becomes a 35mm f/1.2 when attached to the focal reducer.

Should I get a Focal Reducer?

If you don’t mind using manual focus lenses, the focal reducer can be an interesting way to extend your lenses. In theory, you gain a wider, faster lens, and in fact properly implemented, a focal reducer should actually improve sharpness. Broadly, the options are the Speed Booster, and the others. The Speed Booster is a high quality design that performs well with a huge variety of lenses. But at $400, it’s not exactly an impulse purchase. The others, which include focal reducers from Mitakon, RJ Shanghai and Zhongyi are much less expensive ($100-$200) but optically are not nearly as good. As a fun item or for video, they’re probably okay, but I think most serious amateurs would be disappointed with the quality of the images. Personally, despite the attraction of faster (and wider) lenses, I would only consider a focal reducer if I could not find the equivalent lens and could easily afford the Speed Booster.

Is image stabilization available with adapted lenses?

Yes, but only on Olympus bodies, using sensor-based stabilization.

I’m using adapted lenses on my Olympus body. What focal length should I input for the stabilization system?

You should input the actual focal length, not the equivalent one. In other words, if you have a 50mm lens, input 50mm, and not 100mm. For zooms lenses, since there’s no option to input a range of focal lengths, you have to choose one. It’s probably best to input the length you use most often.

Specific Lens Issues

My Panasonic 7-14mm f/4.0 has bright purple flare spots when used with my Olympus E-M5.

Unfortunately, the 16MP sensor used in all Olympus and some newer Panasonic cameras has unusually weak UV filtering. This in conjunction with the 7-14/4’s wide focal length leads to numerous cases of ‘purple spots’ in images with bright light sources. There is a fairly simple mod which lets you insert a gel filter behind the lens to block these spots, but neither Olympus nor Panasonic have offered a fix at this point.

My Panasonic X 14-42mm f/3.5-5.6 and Panasonic X 45-175mm f/4-5.6 lenses show blurring at certain shutter speeds.

While it has become clear that shutter-induced blur, a.k.a ‘shutter shock’ is a fairly common issue with smaller lenses on micro 4/3 bodies, these two lenses are unusually prone to producing blurred images at a wide variety of shutter speeds. Testing with the electronic shutter in Panasonic’s G5 has confirmed that you can basically eliminate the problem if you don’t use the mechanical shutter. That said, the electronic shutter has its own issues (limits to ISO, flash sync speeds and the ‘rolling shutter’ effect).

I see banding in images taken with my Panasonic 20mm f/1.7 lens on the Olympus E-M5.

The AF motor in the 20/1.7 is known to cause interference with the sensor readout, resulting in noise patterns in certain situations. No other lens seems to cause this.

My Olympus E-M5 body sometimes refuses to wake from sleep when the Panasonic 20mm f/1.7 lens is attached to it.

There is a bug with this combination of body and lens. At present, the only way to get the camera out of its locked up state is to remove and then reinsert the camera battery.

My Panasonic 25mm f/1.4 lens makes a rattlesnake-like/chattering noise.

This is primarily a problem with Olympus bodies. The camera rapidly opens and closes the aperture blades in changing light (even if the changes are minimal to nonexistent) in order to keep the amount of light reaching the sensor constant. This is responsible for the noise. It can be fairly loud. Panasonic bodies either do not have this problem at all, or have it to a much lesser degree. A couple of other lenses are reported to cause a milder version of this on Olympus bodies, including the Panasonic 14mm f/2.5 and the Panasonic 20mm f/1.7 although many users also report no problem at all with those lenses.

Last updated: February 7, 2014