EVF vs OVF

Optical viewfinders vs Electronic viewfinders

As mirrorless has been growing, many traditionalists claim they would never give up their OVF, optical viewfinder. And many mirrorless users say that after experiencing a good electronic viewfinder, they could never go back to an optical viewfinder. The point of this post is to attempt an objective comparison between OVFs and modern EVFs.

Before starting, let me say I’m pretty agnostic. I switched from a pretty good EVF camera (the Sony a99), to a good OVF Camera (Nikon D750), which I used for 3+ years before going back to a good EVF (Sony a7riii). OVF/EVF was never a reason for switching. I may now have a slight preference for EVF’s, but not enough to be a deciding factor for me.

EVF vs OVF Speed and Lag

Let’s start with some myths about EVF’s based on their history. Many EVF haters are basing their opinion on cheap EVF cameras, or what they heard or experienced with EVFs years ago. Early EVFs were slow, laggy, grainy. Not what would appeal to any serious photographer.

Even some fairly recent EVF’s suffered from something called the “slideshow effect.” An EVF is a video feed off the camera sensor. OVFs have momentary blackout when the mirror flips. EVFs get momentary blackout when the shutter closes. Very similar when taking single images. If you were taking a burst of images, some mirrorless cameras could not activate the video feed fast enough between frames. The sensor had to devote itself to a high quality image and then a shutter closing — which required to video feed to shut off. As the video feed couldn’t turn on and off 5 or 10 times per second in a burst, Sony cameras would instead show a slideshow of the last image taken. Thus, if you were taking 10 frames per second, you would be watching a slide show 1/10th of a second behind. This was a major impediment to shooting action bursts, as you could lose your subject in 1/10th of a second.

Today’s EVFs

But today’s newest EVFs from Sony no longer have this issue, at least not in the same way. The Sony A7riii, a6300 and a6500 can all behave just like a dslr — Live view with momentary blackouts, at up to 8 frames per second. Above 8 FPS, they still have the “slideshow effect.” Though it should be noted that only the top professional dSLRs can even shoot faster than 8 frames per second.

The Sony A9 takes things to a new level. The a9 is able to display an uninterrupted live video display even when shooting 20 frames per second. This is a combination of using an electronic shutter (as opposed to mechanical shutter) and ultra fast processing speed, pure power. So this is even better than any OVFs as OVFs absolutely must black out momentarily when the image is taken.

So for the most part, the newest EVFs have caught up to OVFs for shooting action, and the best EVFs have even surpassed OVFs in some ways.

But that doesn’t mean OVFs entirely lack any speed advantage. First, EVFs do refresh usually at a rate of 1/60th or 1/120th of a second. So technically, the EVF is lagging by about 0.01 seconds. I find this to be entirely irrelevant, even when shooting the most erratic of action. All cameras have various delays and lags. No camera actually instantly takes the photo when you press the button — there is a tiny delay. A 0.01 second lag is irrelevant in my opinion. But it does exist.

There is another speed area though, where I agree that the OVF has an advantage — immediacy. OVFs work even when the camera is off. Turning on an OVF camera, the camera is ready in a fraction of a second. An EVF is black when off, and takes 1-2 seconds to wake up. This certainly could frustrate some photographers looking to instantly react to a situation, without getting the camera ready a couple seconds before.

Speed/lag summation: The newest EVFs behave much like OVFs with no lag that will affect real world shooting. The best of the best EVFs can give continuous live views, surpassing the capabilities of OVFs. But OVFs give immediacy, which EVFs can’t do.

Battery power:

It’s a fact that an EVF drains more battery power than an OVF. For years, mirrorless had the reputation of being battery pigs. But this wasn’t just due to EVF battery drain. Mirrorless manufacturers were promoting mirrorless as being small, and were therefore using small batteries to keep size down. So OVF cameras had large batteries that the OVF barely used, while EVF cameras had tiny batteries that were constantly being drained.

In their newest models, Sony has increased the battery size and capacity significantly. As a result, battery life is still lesser than a typical dslr, but it’s no longer an astronomic difference.

If you shot a wedding with a camera like the Sony a7rii, you might go through 4-5 batteries in a full day of shooting. With the Nikon D850, you could probably get by with 1 battery but might need a second. With the Sony A7riii, you might get by with 1 battery but will probably need a second.  (Sony’s battery for the A7riii and A9)

So battery summary: OVFs will shoot for longer, but no longer a night and day difference.

Features:

This is the strength and advantage of EVFs.   The EVF is ultimately no different than the camera LCD.  Thus, it can be used to review images, access menus, view histograms, magnify focus checks and much more.

One of my favorite things is the ability to use a clear level gauge/virtual horizon right in the center of the frame:

IMG_0171

 

I find this very helpful for keeping horizons straight, and keeping lines straight when shooting ultrawide.   dSLR cameras may have similar horizons in the LCD, but the OVF is much more limited.  This is a representation of the  view of the OVF from the Nikon D810:

20150605_122311_003

There is limited ability to change the OVF overlay.  The “level gauge” is limited to the arrows on the bottom and side of the frame.  And on the bottom of the LCD, you can get a variety of information using a very basic LCD readout.

Since the EVF works just like an LCD, you can get much more information overlaid with many optional ways to display.  This is actually a photo of the LCD, but it looks exactly the same in the EVF, a full display of information (white balance in this case), as opposed to just tiny symbols on the bottom of the frame.

Many dSLR defenders will correctly argue that they can get all the same information on the LCD, so there is no real value in getting it in the viewfinder.   To some degree, this is true.   But it brings us back to why we value viewfinders in the first place.  Using a viewfinder provides extra support for the camera, it provides glare-free viewing.   So being able to get all the extra information in the viewfinder makes the viewfinder even more usable and valuable.

WYSISYG

What you see is what you get.  Mirrorless fans will recite this as a mantra.   EVFs can simulate the white balance, the exposure level, etc.   As a result, you can supposedly see what your final image will look like, even before you snap the photo.

This would indeed be very valuable except….. it’s not exactly completely true.

The EVF and LCD are presenting a simulation of the final processed jpeg.   If you are shooting raw, it will still apply your camera’s JPEG settings.  Thus, the presented image may look quite different than looking at the raw file in your raw processor.   It is also only a simulation of the exposure level, which my not be completely representative of the final image.   It’s also useless when using a flash.

So an EVF is indeed a tool that can better help you judge the final image, but it is far from perfect.   I do find when using an EVF camera, I tend to do a lot less chimping.

Regular viewing:

Below, see the Nikon D750 next to the Sony A7riii.

img_3483
Nikon D750 vs Sony A7riii

Not all OVFs or EVFs are created equal.   The best OVFs use pentaprisms, they are large, they are bright.   The worst OVFs use pentamirrors, they are small, dark, and they don’t even present 100% of the frame.

On the other hand, even cheaper EVFs tend to be relatively large, bright and show 100% of the frame.

Let’s look at some typical dSLR OVF’s:

Compared to some mirrorless EVFs:

So it is immediately apparent, the cheaper dSLR OVF’s do not even display 100% coverage.  While EVFs are nearly universally 100% coverage, and they typically are larger than OVFs.

The take away is that for cheaper consumer cameras, there is a clear viewing advantage to EVFs.   The Sony A6000 EVF is much larger than the Canon Rebel, it shows 100% coverage.  I know some people will stubbornly say that they will take any OVF over any EVF.  But in my opinion, such a stubborn statement is like saying I would rather have a rotten worm infested Golden Delicious apple than a perfect fresh crisp Macintosh apple.  Larger, brighter, 100% coverage:  these are big advantages.

On the other hand, these advantages are not so significant when looking at premium cameras.   The largest OVF on the market is the Nikon D850 at .75 magnification.   While slightly smaller than the A7riii, they are close.  They both show 100% coverage.   The D850 OVF is bright.

Finally, OVFs can have a narrow “viewing” advantage over EVFs at times.  Since the EVF is a processing image, it has less dynamic range than can be viewed with the naked eye.   Thus, when looking at a high contrast scene, you may see more detail in an OVF than with an EVF.

In summary, for regular viewing in regular light, I would strongly recommend a mirrorless EVF over a dSLR OVF among entry level and consumer cameras.  But among premium cameras, there is more equality and the pros and cons are more evenly weighted.

Low light viewing:

Critics of EVFs will claim that EVFs do very poorly in low light.  I actually have the exact opposite experience.   This was my test scene, very low light, taken with iphone:

img_3472

The iphone image is very grainy and dark, because this was very low light.

I then held the iphone up to the Nikon D750 viewfinder:

img_3475
Nikon D750 low light viewfinder

The traditional dSLR OVF, even a good OVF, is still darker than the regular scene.  Thus, in low light, you can just barely see anything.

On the other hand, the Sony A7riii viewfinder:

img_3479-1
Sony A7riii EVF in low light

Big and bright, even in low light.   Some will claim that the EVF becomes grainy in low light.  But even grainy is better than totally dark.

Conclusion:

The choice of mirrorless or dSLR often is reduced to the difference between OVF and EVF.  For the most part, these differences are exaggerated by people in both camps.

Among consumer cameras, EVFs have a clear advantage of being bigger, brighter and 100% of the frame.   Other advantages of EVF, such as “WYSISYG” are a bit exaggerated.   Meanwhile, these consumer EVFs tend to have small batteries, leading to cameras with terrible battery life.

Among semi-pro, enthusiast and professional cameras, these is even less difference between OVF and EVF.   They all do 100% coverage, they are all fairly large and bright.   Mirrorless EVFs may be even larger and brighter.  They have the advantages of additional feedback and information displayed in the viewfinder.  dSLR OVFs have the advantage of immediacy, no 1-2 second start up time.   The OVF can be better for viewing a high contrast scene, while the EVF can be better for viewing a low light scene.

Any skilled photographer should be able to easily adapt between EVF and OVF.   For the most part, neither should be a game changer.

In the future, I expect EVFs to gain more advantages.  I’m looking at the Sony A9, which uses a blackout free viewfinder.  Frame rates of EVFs will only continue to increase.  They will get faster, start up delays will be reduced to irrelevance.  And ultimately, the camera manufacturers can make EVF cameras more cheaply than OVF cameras.   The pricing advantage will make a future of EVFs inevitable.   But for now, the serious enthusiast photographer can be equally well served by either.

For more on the present and future of the mirrorless, click here.  

 

 

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