Especially in HDR photography, and also on my blog, you may have seen EV being used quite often. And today, together we will look at what EV means, and how you use it.

EV – Exposure value

In the first part of this series, I talked about Exposure. As I explained, exposure is about how much light you let into your camera. Exposure value (EV) is any combination of shutter speed, aperture and ISO (some don’t include ISO, but I think it should be included) that yields the same exposure for a specific fixed amount of light.

On your camera, you will see a scale with 0 in the middle, mostly going from -2 to 2 or from -3 to 3. This shows the current EV value.

If the value is shown as 0EV, this means, that the set settings for shutter speed, aperture and ISO together allow for an exposure, that is correct based on the cameras own metering of the current scene. If the EV is a negative number, that means that the resulting photo will be underexposed, if it’s a positive number, it will be overexposed. There are no specific settings for 0EV, as it changes based on available light, camera mode, lens and what from the three values you have changed yourself.

When you take 0EV as the amount of light you need the capture for proper exposure, than +1EV is double the light, +2EV is four times the light and so on. -1EV is half the light captured, -2EV is quarter and so on. So the amount always doubles or half’s, based on which way you go. EV can also be set in fractions, like 1/3rd, 2/3rd’s. On some cameras you can switch this to use half’s.

To double the light, so going one stop up, you either double the time, double the ISO or double the aperture. This is easy to count for shutter speed and ISO, where you just double the number. For aperture, this is not so straightforward and an aperture table is needed. For instance to double F8 you go to F5.6, to double F5.6 you go to F4 and so on. But since every-time you change any of these values on your camera, they change by 1/3rd EV. So if you change the value three times, it will change by 1EV.

For instance, if you shoot in the Aperture priority mode, and you have a scene where f2.8, ISO 100 and 1/10s will result in correct exposure, that is 0EV, than also f2.8, ISO 200 and 1/20s will give the same result, f.4, iso 100, 1/5s, and so on. Each time you change one value, one of the other two has to change to compensate, for the EV to stay at 0.

Exposure compensation

First use for EV and their understanding is Exposure compensation. It probably happened to you, that you have been shooting in a certain conditions (snow covered landscape is a perfect example here) and all you photos came out too bright or too dark. Thats because your camera has problem determining the correct exposure. In this case you can compensate for this, by forcing the camera to take a positive or negative value EV instead of the 0 one.

So for instance, the mentioned snow example, cameras tend to underexpose in those situations. So by setting the exposure compensation to +1/3EV or higher, you will force the camera to overexpose every photo, so compensating for the problem.

Using exposure compensation is different on every camera, but mostly there is a wheel you turn to do so in the menu, or there is a specific wheel with EV markings on it. These have no effect in the Manual mode, as there you have to compensate manually by changing the aperture, shutter speed and ISO values.

Exposure bracketing

Exposure bracketing, is taking (or setting the camera to take) multiple photos with different EV values. For instance you can take a series of 5 photos, at -2EV, -1EV, 0EV, +1EV and +2EV.

This is for instances, where you know, that not everything will be exposed in the 0EV photo properly. Again, a typical example would be having a bright sky on half of the picture. Either your scenery, or your sky is properly exposed, but usually not both. Having multiple photos with different exposures, will endure you, that you have one with properly exposed sky and one with scenery. With those, you can then continue as you need, blend them, use HDR or similar.

And advance mode would be just to manually bracket for the EV values you need, and not even do the whole series.

You can take a look at my article about taking brackets for HDR, where I also included a video that shows exposure bracketing.

All the exact exposure values can be also calculated using mathematical equations, but I don’t think you will ever need it in the field. When taking photos the camera doest that for you :)

There are only 7 days left to join my Photo editing contest sponsored by Aurora HDR and get a chance to win an Everyday messenger bag. So don’t leave it for the last moment and head over the the contest announcement page, to get the full rules and all needed files to enter the contest :)

Many of you have already joined, and for those who need a bit of inspiration, here are some of the entries that I already received. You can see many more in the contest event on Facebook. It’s always so interesting to see how different the result is when different photographers edit the photo, isn’t it? :)

This is one strange winter. There is so much moisture in the air in Bratislava, that it’s covered in fog almost all the time. And it was again the same today, so I thought I get a look from higher up. I went to the top of the SNP bridge and this is what I got. Not that I was there that long, it was crazy cold and windy, and the moisture started condensing on my camera ant tripod right away.

Interestingly, I don’t remember the light in the middle being there before, and with it, they actually made taking photos from there much worse as it shines directly towards the viewing platform. Good that I already have so many photos from there, bad that everyone who tries to take photos from there from now on, will have to deal with it.

This is a single exposure, edited in Lightroom and Photoshop.

Technique: Photoshop Edit, Number of exposures: 1, Camera Model: Sony a7R + Metabones MkIII Adapter, Lens: Canon 16-35mm F2.8, Focal length: 34mm, Aperture: 11, Middle exposure time: 8s, ISO: 100, Tripod used: yes, Location: 48.136692, 17.105281

For bigger things, I did a review for, I like to do a follow up after few months, to make an update on how it is to use them. And since it just has been two months I got the Surface Pro 4, today I will share with you how it is.

Stability & Reliability

For the whole time I was a part of the Windows Insider program. So the version of Windows 10 I used on the Surface Pro 4, was always the newest one from the fast ring. If you are a part of it, you know that Microsoft is releasing a new version of windows almost weekly now. I also always kept all software up to date.

In the two months, I had a blue-screen error once. I had no other errors, restarts or hiccups at all. The problem with the crashing video drivers was corrected few days after I posted my review. Actually, the only repeating problem I found is a bit strange one. When I use hibernate, after the Surface wakes up, I sometimes can’t stream video to it. It’s just crazy choppy and slow. Not sure if this is caused by the wifi driver, but a restart always solves it. But this is more of an annoyance than a real problem.

Keyboard & Pen

I thought I would not like the keyboard. I write with all 10 fingers and my normal keyboard is a MS natural ergonomic keyboard, so much bigger, angled and split in the middle. But to my surprise I really like the keyboard. It’s big enough for me to work it, it is not that bouncy and it’s very responsive. I did write quite a few articles for the blog while laying in bed with the surface on my knees and it was still fine :). The touch-pad works OK, but I got a mouse for the surface, so I prefer not to use it.

I have not used the pen for editing at all. But I did use it for taking quick notes, to mark up web pages (it was great when I was preparing the page update, just loading a work in progress version into edge and then use the pen to note needed changes right there) and I tried a bit of drawing, not that I really know how to. I got a program called Mischief, which is an endless drawing/note taking canvas, and that is a great companion to the pen. All the time I had 0 issues with it.

Both keyboard and pen magnets are strong enough to hold them in place and not even when putting surface in the bag either of them ever got loose.

Performance & Battery

I haven’t done much photo editing on it recently, but I did quite a lot of other Photoshop work, like creating flayers and similar. I was very pleasantly surprised by how it managed to keep up and even after hours of work I never heard the fan. Once I even forgot to plug in the power cord, and I haven’t noticed it at all for over three hours.

There were of course instance when it got taxed quite more. Especially when working in Ligthroom, the fans come on rather quickly. But in a more relaxed situation, having few Edge tabs open, video playing in the background, and few more apps, I never once noticed them on. Actually, mostly they turn on when you just leave the surface on and you do nothing. The system then starts to probably do some maintenance tasks and heats up for few minutes.

On average I was getting around 6 hours of battery in my use. Maybe not the best, but enough for me.

Durability & Software

In the two months I got no scratches or any other blemishes on the Surface. But since I’m always very careful with my things, that is not really a surprise :)

My favorite feature of the Surface has to be Windows Hello. It works for me 100% of the time and I have not needed to type my password once after the initial setup. This really should be standard on every single PC. Also Edge was the only browser I used, as it is great with scaling web pages on such high dpi screen.

The system boots up crazy fast, and I have not seen a real difference between full startup and hibernation.

Conclusion

I have not turned on my Nexus tablet once in the last two months. That on its own should tell you how satisfied I am with the surface as a tablet. Once one gets used to some different controls, it’s just great. On the other side, it’s also a really nice laptop. It’s so small when placed in a bag and still really powerful.

One of the issues when creating a Panorama, are the missing areas around the sides, due to how the images have to be warped to fit each other. To correct this, one needed to either cut off the areas, fill them in or try to war the image to get rid of them. With the newest update to Lightroom and Adobe Camera RAW, there is now one more option, called Boundary warp.

Here I’m showing it to you in Lightroom, but it works exactly the same in Camera RAW. To be able to use it, you have to first merge a panorama in Lightroom. To do so, just select all the files of the panorama, right click one of them and choose Photo merge/Panorama, or go from the top menu Photo/Photo Merge/Panorama, or even faster, hit Ctrl+M.

Once you get the popup window, you will see the merged panorama. If you have Auto Crop on, you have to turn it off first, to be able to see the whole photo, including the missing areas. Now here you also see the Boundary warp slider. Move it to the right, to see how the photo will start warping to fill in all the missing areas. It will also try to straighten the image while doing that.

Here are three different situations, and how it worked out. I this first one, a scenery landscape, it worked out perfectly. The sky looks great and even the road was straightened perfectly.

In this second example, it was not that perfect. This is the biggest weakness of Boundary warp. If you have straight lines close to the warped borders, Boundary warp can distort and bend them. You can see it here on the right, where the bridge is just not straight. In this case, one would have to either crop this away, try to warp it back in Photoshop, or tone down boundary warp, to a lover setting, where this is not so visible. Either way, more work is needed.

In this last example, here again are straight lines close to the edge. But since the needed warp is much smaller, there is no visible distortion in the final image.

Boundary ward is a really nice addition from Adobe. It will make some quite challenging panorama corrections that much easier. And it even leave the result in RAW DNG format, which makes it even better.