My Camera Must Have an Electronic Viewfinder

My Camera Must have an Electronic Viewfinder

Why I hate Optical Viewfinders

Author  Andrew S   May 2013

 

Abbreviations used in this article   ELV= Eye Level Viewfinder, BIELV= Built in Eye Level Viewfinder,  EVF= Electronic Viewfinder, OVF= Optical Viewfinder, MILC= Mirrorless Interchangeable Lens Camera, DSLR= Digital Single Lens Reflex Camera, SLT= Single Lens Translucent Camera [Sony only].

Introduction  I sometimes read expressions of opinion by bloggers and contributors to user forums that EVFs are inferior to OVFs.  I present here a case for the EVF.

The argument for a BIELV  Before we get to debating the OVF vs EVF question, I want to summarise the arguments for having a BIELV.  Most cameras, mainly compacts and MILC's, do not have an BIELV.  I think they should because:

1. Options  The camera with BIELV gives the user the option to use it or not. There are plenty of situations (see below) when a BIELV is desirable. If it's not there the option to use it is denied.

 

2. Differentiation  The biggest current threat to the camera as a species of useful device is the smart phone which takes photos which are good enough for most user's requirements. So why buy a camera ? Because it has better image quality ? Yes, but the concept of image quality might be a bit abstract for a potential buyer who thinks their smart phone pix are OK.  But smart phones do not have an ELV. So there is an ergonomic selling point for cameras with  BIELV which most manufacturers have not fully embraced.   Fuji has fitted it's X10/X20 compacts with a BIOVF.  The first compact [I think it is the first] with BIEVF will be the [Panasonic] Lumix LF1 which was announced in April 2013 for delivery in June 2013.  I think that camera makers need to provide and promote their products with features which smart phones do NOT have, like a BIELV. Instead the latest crop of cameras appears to be marketing features such as wireless communications, which smart phones already do better.

3. Steady Cam  With eye level viewing a camera is much steadier  than when it is held out in front for monitor viewing. This can make a big difference to image sharpness with long lenses or in low light with slow shutter speeds.

4. Sunblock  Even the latest and best monitors are difficult to use in full sun. The preview image itself is often washed out and the camera data may be impossible to read.

5. Distractions  There are times when the photographer wants to talk to the subject, in which case monitor viewing is desirable. But when the photographer wants cognitive separation from the surroundings to concentrate fully on the subject, then eye level viewing is very desirable.

6. Clip Ons are a nuisance  If the only option for eye level viewing is a clip on OVF or EFV it will invariably be somewhere in the bottom of the camera bag, or left at home when required. Then there is the nuisance of finding the thing and clipping it on, by which time the subject will likely have wandered away. If the accessory viewfinder is left on the camera it makes the camera very tall,  difficult to get in and out of a bag with increased risk of damage to the VF or it's attachment to camera body.

So, having established that the BIELV is a good idea, let us specify what tasks it might reasonably be expected to perform. Having done this we can investigate whether the OVF or EVF is more effective  for each task.

 

BIELV Task List

1. Framing  Most EVF's offer 100% accurate framing, which comes as no surprise as they take data directly from the imaging sensor. Some high end DSLRs do likewise, but most DSLRs offer a reduced view of the subject. All "rangefinder" style OVF's have at best, approximate framing with the added problem of parallax error. Many cameras allow different image aspect ratios, which are easily represented in an EVF but not an OVF.

Best: EVF

2. Preview The preview experience offered by an OVF is fundamentally different from that of an EVF.  A good quality OVF provides  a  representation of  the scene in front of the camera. But I can see that without a camera. I want the camera viewfinder to provide me with an accurate preview of the photo which is about to be taken. This includes brightness, the effect of exposure compensation, highlight and shadow detail, color balance and sharpness.  A DSLR OVF can tell me about sharpness [a rangefinder OVF cannot] but the other qualities can only be conveyed by an EVF.  That is not to say all existing EVFs actually achieve the level of preview accuracy that I want. In fact I would say most of those I have used are one or two development generations short of  an ideal viewing experience, but the potential is there with technological development.

Best: Close call. I give it to the better EVF's right now. In a year or two there will be no contest.

3. Information/Data Displays  An  OVF cannot convey much in the way of information in addition to the framed scene. Manufacturers have used various strategies to improve the information visible on or near an OVF view. These include camera data beneath the image and various types of information projected onto the image frame.  An  EVF can be configured to give the user choice of  "DSLR" view or "Monitor" view with camera data beneath or superimposed on the image preview. A choice of grid lines can be displayed. Many other items can be displayed, or switched off by user choice. These might include highlight/shadow clip warning, focus peaking, electronic two way level gauge, histogram, camera shake warning  and any of a host of information icons which can be switched to display or not display by user choice.

Best: EVF

 

4.  Responsiveness/Refresh Rate   This is an issue when panning especially in low light, and is a major factor in following action with high frame rates and continuous AF.  An OVF refreshes at the speed of light [literally] so has the initial advantage. The limiting factor for a DSLR is the flipping mirror. With an EVF the limiting factors are the sensor read rate and EVF  refresh rate expressed as frames per second.  With present technology the flipping mirror can move faster than electronic processing. So for high frame rates the OVF is currently ahead. However DSLR/OVF technology reached it's full potential several years ago, but electronic processing speed is increasing every year.

Best: OVF  [for now]

5. Monitor/ELV segue  A fully electronic monitor/EVF system can be configured to provide the same information presented the same way in both the monitor and EVF.  This facility is not available with OVF.

Best: EVF

6. Focus operations

Autofocus:  An EVF can display the active AF area position and size, with AF confirmation. OVF's can provide a similar facility by means of projection/overlay. The EVF  arguably  provides a more integrated user interface.

Manual focus  An EVF enables automatic [or user selected] enlargement of the center or other part of the frame to aid MF accuracy. Other technical features such as focus peaking can be offered.

Best: EVF

7. View without switching on  OVF can, EVF can't.

Best: OVF

8. Size  The size of a DSLR  OVF is related to the sensor size. The apparent size of an EVF  preview image is unrelated to the capture sensor. This means DSLR's with 43 mm (diagonal) sensors provide big bright OVFs, but DSLRs with smaller sensors have smaller and less appealing OVFs. Micro Four Thirds camera with even smaller sensors can provide a  big bright EVF view just like a large DSLR.

Best: EVF 

9. Clarity/Sharpness  With present technology, the best and biggest DSLRs  and the best rangefinders have OVFs  providing the best clarity and sharpness. Budget  DSLRs are considerably less impressive. EVFs vary from excellent at the top end to awful at the budget end of the market. EVFs are improving but are not quite at the level of the best OVFs yet.

Best: OVF   

Conclusion  I don't really hate optical viewfinders, I just think they are last century's technology. The best ones still have an edge over good EVFs in some aspects of performance, particularly in the areas of responsiveness and refresh rate. I would also like to see better highlight/shadow detail in the EVFs which I have used recently, mostly in M43 cameras. In other respects the EVF  already provides many advantages. EVF technology continues to evolve while the OVF in it's various manifestations reached a development limit many years ago.