Exposure Value (EV) and Exposure Compensation
Exposure is defined as how much light hits the camera’s sensor. It depends on the camera settings mainly aperture and shutter speed. Exposure Value (known as EV) is a number that represents the exposure setting of the camera. We will explain what the number means and how it is used for Exposure Compensation.
The exposure depends on two things: how much light gets through the lenses to the camera’s sensor and for how long the sensor is exposed. The former is a function of the aperture value while the latter is a function of the shutter speed. Exposure value is a number that represents this potential amount of light that could hit the sensor. It is important to understand that exposure value is a measure of how exposed the sensor is to light and not a measure of how much light actually hits the sensor. The exposure value is independent of how lit the scene is. For example a pair of aperture value and shutter speed represents the same exposure value both if the camera is used during a very bright day or during a dark night.
Each exposure value number represents all the possible shutter and aperture settings that result in the same exposure. Although the exposure value is the same for different combinations of aperture values and shutter speeds the resulting photo can be very different (the aperture controls the depth of field while shutter speed controls how much motion is captured).
EV 0.0 is defined as the exposure when setting the aperture to f-number 1.0 and the shutter speed to 1 second. All other exposure values are relative to that number. Exposure values are on a base two logarithmic scale. This means that every single step of EV – plus or minus 1 – represents the exposure (actual light that hits the sensor) being halved or doubled.
It is not likely that you will find yourself setting absolute exposure values. Most cameras do not support entering exposure values at all. You will however use exposure values when setting exposure compensation. Exposure compensation is a way to set the camera to an exposure that is lower or higher than what was automatically detected. The camera auto exposure setting is not perfect and in some scenes results in over or under exposed photos. In such cases exposure compensation can solve the problem Exposure compensation is also useful when you like to get photos that are a bit over or under exposed.
When setting exposure compensation you select an exposure value that is added to the current exposure setting. Usually exposure compensation values are no more than +/-5 EV. For example a compensation of -2EV will make a photo darker (or less exposed) while a compensation of +2EV will make it brighter (or more exposed). A good example of using exposure compensation is on a bright day. Compensate to lower exposure using a value of -0.5EV or -1EV to get richer colors and more details.
Exposure values can also be used in conjunction with auto bracketing. When using exposure auto bracketing each time you take a photo the camera takes a series of extra photos for you each with a slightly different exposure. You can set the EV step between each photo.
Meall Corranaich & Meall a’ Choire Leith
Leaving the house at 6am I did feel I was a little mad but I had high hopes for the day and with the roads virtually deserted for the duration of the drive I found myself parked in the lay-by around 07:30am.
It’s still dark, what the hell am I playing at! The moonlight reflecting off Lachan na Lairige, the snow capped tops of Beinn Ghlas and Meall nan Tarmachan had been in my view as I made my way up the slippery access road passed the visitor centre. Despite the darkness, this really looked like it was going to be a really good day. All I can say now is what a difference 30 minutes makes.
As I set off the cloud had rolled in reducing visibility somewhat. Drat!!
I follow the path up and onto the moorland, first slip and I am on my knees. My bright yellow (see me here) jacket now tainted with brown boggy mud, aaargh. I reach the end of the path that has been constructed then look for the fence posts which everyone says to follow.
I see one, make for it then look for the other… Where is it? The mist has lifted a little but not by much. Suddenly I have this feeling of being watched!! I look on and see a rather large herd of deer looking back at me. It’s a little lighter now but still dark enough to confuse the hell out of me. I mean, I am on my own in the middle of a peat bog, not a breath of wind, and all these animals staring back at me. Carry on Ali, they’ll move on I think to myself, next time I look up there gone, and there must have been at least 15 or so…
Higher up I move above the snow line, and find a set of footprints, iced up and I reckon possibly from the day before. Map, compass and GPS at hand I follow the footprints up through the snow and then discover there has been a dog with this person too.
With the snow drifting in places I soon found myself on the summit ridge heading towards Meall Corranaich. The sun by now was visible through the cloud brightening the place up and to my advantage some breaks in the cloud appeared to, to give me some good views towards Killin and over Coire Odhar to Beinn Ghlas.
Crampons!?! How good it would have been to have a set right now as I made my way up the windblown path covered in frozen ice and snow. Slip once, slip twice, and oh darn it as I went down again. Finding another way, I moved just off the path and into the fresh snow. Christmas list for Santa – add Crampons pleeeease…
The summit, a desolate place with not a lot to look at. The usual pile of stone but not as you would know it. Rather than a tall stone structure there was this pile made to look like a squashed sponge cake, in my opinion, but with the added effect of old unused fence posts protruding from it. Icing on top due to the snow coverage, it was just missing the cherry.
Its 10:15am, time to move on. Take a bearing, and check the GPS, so far so good that I am still on track. I had read that it’s not unusual to head down the wrong ridge when making your way toward Meall a’ Choire Leith. Thinking on this I stick to the ridge line keeping the cornices in view. Deep snow hampers progress in parts and as I am making fresh tracks my pace slows a little. Check the GPS again, still on the right line. Moving on I then notice I can’t see the cornices anymore. I am still on the ridge so I retrieve the GPS again, and yes I have followed the contour of the ridge and gone off track (I had the GPS loaded with the route). Easy done though and it’s not long before I am back where I should be.
Dropping off the ridge to the bealach I pause for a few moments as I can see down Coire Gorm and Coire Liath. One side caked in snow (Coire Liath) more than the other. Given the weather over the past week it would come as no surprise. A bite to eat and a quick warm cup of tea I start my way up the shoulder to the second summit of the day.
Two sets of footprints this time, one with crampons attached but alas not fresh. The cloud has lifted enough though to see the way with the path being very prominent, so navigation was hardly likely to be an issue, until I got nearer the top and it just disappeared.
Making a direct approach to the highest point soon brought the summit cairn into view. Would the white block of rock still be perched on top that I had read about in another report on the Scottish Hills website?
I reach the cairn with a huge Fog Bow in my presence, scrape off some snow and there it is. Not on top though. It looks as though some other walkers had been along and increased the size of the cairn. I settle down for lunch, it’s still with no wind to reduce the temperature, I tuck into my sandwiches, fruit, Jaffa Cakes and that all important flask of tea.
Finishing up I take a bearing and head off the summit in the direction of Coire Gorm. It didn’t take long and I found myself out of the cloud, below the snow line and making my way towards the first river crossing.
Mud, mud and more bleeding mud. The walk out could be a trip report in its own right. It was wet, very wet, muddy and just annoying. The chance of getting a pace going was practically impossible. Slip and down I go, back up, walk, and slip again. Splattered in mud I carry on, the herd of deer that have reappeared are no doubt having a laugh at my expense.
I reach the second river crossing, bearing in mind the recent weather the rivers are a little deeper and faster running, or at least I think so anyway. With a hop slip and a jump I’m over and into the next path of torturous mud, and it’s uphill???
I had a little cramp in the legs and this was the last thing I needed. It’s just no fair this over-grown baby said to himself!! It really did feel like one step forward, two steps back at times but in the end I made it back to the path and the car. De-kitted and changed into fresh clothes (I always carry a spare change thankfully) I made my way back down the road passing a somewhat busy visitor centre car park. Busy day there then given that I had two Munros to myself that same day…
Geal Charn (Monadhlaith)
Day two of the weekend and after the previous days exploits on Aonach Mor it was questionable as to whether my legs would hold up on another walk. The last time I walk on two consecutive days my legs said no more and I had to call a halt half way through…
We were after an easy walk this time, with Ian and Rick having a long drive south that same day it was decided to go for an easy solo Munro that wouldn’t be too tiring. We settled for Geal Charn (Monadhlaith), an easy going walk of 926m.
Parking up at Garva Bridge we set off along the road, crossing the River Spey and following the land rover track out onto the open hillside. No discernable path to follow we simply broke our way through the heather until we picked up a path further up the hillside. It was chilly, with blue skies and sunshine above, not a breath of wind, it felt surreal to be in the middle of nowhere.
Following the path we crossed the Allt Coire nan Dearcag making for the south-west ridge. From there a simple stroll so to speak up the ridge to the summit, and the whole time, my legs surprisingly just kept wanting to carry on.
At the summit we settled down for lunch, taking in the views, peaceful, quiet, snow-capped moutains in the distance. The Cairngorms, the Ben Alder massif, Creag Meagaidh range. The usual photographs taken we finished up and retraced our steps back to the car park.
Aonach Mor
Yet another of those hills which was so nearly conquered all those years ago but with fading light and tiredness saw the walk cut short. I had spent that day with my brother traversing the entire Grey Corries Ridge, Aonach Mor being the final summit of the day, but with the light quickly fading and snow making progress hard we chose to descend into Coire Giubhsachan to strike camp as we were climbing the CMD Arete and the Ben the following day…
Just last weekend, a few friends and I arranged a weekend staying in the Aite Cruinnichidh just outside Roy Bridge. Splendid place, thoroughly recommended. I arrive late on the Friday night due to work commitments to find the other guys already tucked up in their bunks, try not to make too much noise but it doesn’t last…
Up bright and early the next day at a god-awful 06:30 or thereabouts, chilly but bright and promising. Breakfast, packed and off we venture into the unknown, well the Aonachs actually. They want them both, I want just one so we’ll see how things pan out I think to myself.
Arriving at Nevis Range car park, the summits in cloud, the snow line just over the Gondola top station, time to get the legs burning on the first part of the ascent.
Following the line of the Gondola track it a short while later that the whir is heard and the first of the Gondola’s pass by, damn that looks good I think to myself puffing and wheezing as I make my way up the downhill mountain bike track.
Reaching the top station, a little break and a bight to eat saw us on our way up into the cloud and snow. As usual, my legs have had enough and I slow to a pace that leaves me lagging well behind. I see my friends disappear and reappear a few times in the cloud before finally vanishing from sight. See ya when you get back then I guess…
I trudge up at a steady but slow pace, finally reaching the top of the tow, my feet buried in drifted snow. A little further and I am on the ridge, but somewhat shocked at how close the path I am following is to the cornices overhanging the cliffs. I take it easy and carry on, following the 4 sets of footprints set out before me.
Another tow line, ski fences and a Vodafone communications tower, I carry on into the clag eventually coming across a small cairn. Is this the summit, nah cant be but is it I wonder. The land is descending away from me but something just didnt make sense.
A big 4000′er with a small cairn to mark the summit. Some how I doubt it and choose to carry on again following the footprints made by my friends. I would like to point out that I do not make a habit of following footprints in the snow and will keep checking the map and taking a compass bearing. On the other hand though I knew John had his GPS on hand so was pretty sure we were heading in the right direction.
The footprints led straight to a large cairn caked in snow. A hand print on the top so I knew I was there. The guys by now long gone onto their next target, Aonach Beag. I on the other hand was more than happy to have summited Aonach Mor bringing an end to that excellent ridge walk done so many years ago.
I head back as it was not the place for hanging about. Stopping at the Vodafone communications tower to find some shelter and get some nurishment into me. Whilst walking back the weather was coming and going ginving me glimpses of sunshine as the cloud cleared momentarily. Was there going to be a break in the weather so I could sit and have my lunch in the sunshine.
I arrive back at the communications tower as the weather breaks and I stand there surrounded by crisp white snow, blue skies and sunshine above me, not a breath of wind, it was just so peaceful and enjoyable.
Not missing the opportunity the camera quickly comes of the disposed of rucsac. I race about leaving footprints everywhere getting pictures of the ski range, the CMD Arete and part of the Ben, the cornises, I just wanted to savour the moment in print.
I settle down for lunch sitting in the snow wondering where everyone is, my friends probably by now making their was back over Aonach Mor to where I am. Half an hour or so passes, the clound has come in again and the guys appear. It would appear that they never experienced the break in the weather so I try not to heap misery on them but for sure the camera will be out later to show them what they missed.
We make our way back down the ridge picking up our ascent line and descend out of the cloud down towards the Gondola station. Who’s up for the walk back down the mountain bike track or will be lazy and hop onto the Gondola. No fear like, the Gondola won without a debate.
We jump on, the guy just looking at us. Arent we meant to pay for this? Maybe at the bottom I guess, like we have any money on us. The Gondola stops just over half way down, damn they’ve rumbled us, quick lets jump out and hide as we sit there dangling high above the ground.
It starts again a short while later and we get off at the bottom, no-one to pay, no-one bats a eye-lid as we just simply walk out. Well, we did put in the gruelling hike at the start so felt it worthy of the return to try it out…
A splendid day was had by all…
Beinn Dorain – History repeating itself…
Some 16 years ago I set out with an old friend to climb two Munros. The weather was somewhat awful, thick cloud and pouring rain which seemed to be a regular occurrence back then. We made good progress up through the Coire, attaining the summit ridge in good time and summiting the first Munro without any problems.
Given the weather a compass bearing was taken to return to the col and due to sheer volume of water, the path was nowhere to be seen. Somehow we went off course and descended into the wrong valley, meaning in the end when we discovered the error of our ways, a long walk back to the car. The second Munro eluded us that day and despite passing this Munro countless times I never once returned, until yesterday…
I sat on Saturday night wondering where to go seen as it would be just myself heading out. I originally thought of Sgiath Chuil and Meall Glas but wanted something a little more exciting with good views. I settled on the original two I thought of in the first instance but secretly planned this other Munro depending on the weather, and also given the fact that I need to play catch up on you guys.
Wakened at about 4am I nearly switched the alarm clock off when I heard the rain lashing down outside, didn’t though and thank goodness. I left the house just before 7 driving north in sunshine with very little cloud. Sgiath Chuil and Meall Glas with their summits in cloud looked good but Ben More and Stob Binnien looked amazing with no cloud cover and the sunshine gleaming on the slopes.
I decided to keep heading north, well if the weather was this good lower down then it must be a tad better further on. Pulling out of Tyndrum and rounding the corner, she burst into view. Your mine I thought to myself, her slopes rising to the coned, rocky summit, the train skirting the lower side of her flanks. Stopped and got that all important picture.
Pulling into the Station car park at Bridge of Orchy just after 8am I hastily got ready. A few midges I can deal with but within seconds there was a whole swarm of the sharp-toothed buggers doing untold damage to my skin and well-being. Allsorts thrown into the rucksack I decided to get the hell out of there and sort the pack out on the open hill side. Shorts and t-shirt weather it was as I made my way up the coire once more. Not a sole to be seen, although it wasn’t too much longer before I was overtaken by an older gentleman and a runner. One last sharp pull and I was on the col. Views to Mhanach, Dothaidh, the Etive hills and the Black Mount and of course my intended target, Beinn Dorain.
A little cloud suddenly skirting the summit ridge but I was sure it would burn off. My fitness must be improving gradually as I found the walk up the ridge easy going, either that or it was just the fact that I was enjoying the time. Further on I noticed a large cairn, too big to be a marker point I thought so it must be the summit. But wait, I had read about this being a false summit which many mistook for the summit in poor weather and I can see why. On reaching this oversized cairn I could see the true summit, just a little further on with a shallow dip in between.
I stood on the summit just before 11am, waving frantically at the coaches, cars and motorbikes whizzing past below – did anyone see me I wonder.
I returned to the “other” summit and settled down for some lunch. Where was everyone? I was alone 3,000ft up basking in the sunshine and not another sole to share it with. A gentle breeze helping to cool things down I just simply sat there enjoying my lunch and the views. Descending the ridge I passed one lad, had a quick chat and carried on, reaching the coire and coming face to face with what seemed like a coach-load of folk heading up. I left them to it, panting and gasping for breath making their way up. I returned to the car, thankfully no midges, changed with a bite to eat and a cool drink and headed off home a happy man.
A Two-Wheeled World?
I have had a long-time passion for motorbikes, but I just never got round to actually learning how to ride one safely and compatently. In July 2008, I plucked up the courage to enlist on one of these all intensive courses designed to get you through the UK Motorbike Test within just a few days.
First passing the CBT (Compulsary Bike Training) which is like spending just one day learning some maneouveurs and then taking a 2 hour ride on the open road on a 125cc class of motorbike. Thankfully, having been driving a car for about 17 years does help, as I didnt feel that concerned about all the other road users. Unfortunately I dont think the same could be said about the teenager riding their moped at the same time.
Taking a weeks holiday, the time came to progress onto the 600cc class of motorbike and this is what I would spend the next few days riding around on and eventually sitting my test on.
What a difference. The power, the acceleration, the weight but I did find it a lot easier to control. I was riding a Honda CB600, bright orange so I definately stood out. The first day I was on the back roads riding around housing estates. A little over-confident to begin with I was soon brought down a peg or two by my instructor being reminded that it’s all about safety while obviously getting enjoyment out of it. It was then out onto the open road before returning for some lunch at XLR8. After an hour or so, it was back in the saddle and off out for another hour or two. However, tiredness was now taking effect and I started making silly mistakes. My instructor called it a day and we returned to the training centre.
The following day it was more of the same but I could feel the confidence growing. I was buzzing about the town, opening up the throttle on the open roads and carrying out those all important maneuvours. The dreaded U-turn, the emergency stop, walking the bike etc. Thankfully not once did I loose control at slow speeds and went home that night feeling great knowing that I wasnt too far off being ready for the test.
The test was set for the Thursday morning of that week at 10am. With the first two day intensive training out of the way just one remained before the day of the test. This time it was a half days training concentrating on the maneuvours. The U-turn which on occasions I now found myself putting the foot down started to annoy me. However, its all in the mind and once explained again for the umpteenth time I managed to get it right. “Try turning the bike around” my instructor said, easy done. When he mentioned do a U-turn though the nerves kicked in. In the end though the difference between a U-turn and turn the bike around is nothing, it’s just the way the mind interpretates the statement as I found. A quick buzz around the roads and the day came to an end. Test time here we come.
Thursday morning arrives and I’m a little nervous. I’ll just do the best I can and see what happens I think to myself. I arrive at the training centre just before 9am as I have a one hour lesson prior to the actual test. I look about, no sign of the bike I’ve learning on, where the bloody hell is it!?!
I ask inside, to find that someone else is taking there test and needs use of the bike. Fair enough but what I am meant to do. One Yamaha 600cc bike later and I am on the road. Doesn’t feel right but I make do, thinking that it’s not what I want right before I am due to take the test. I get through it though and arrive at the test centre ready for action.
My instructor takes me in and introduces me to the examiner, and then leaves. Kitted up with the radio equipment the examiner takes me out and asks a few questions, no worries and then he lets me know that he will be following in the car. Okay of we go…
I listen to his instructions, hoping that they will come through quickly and I settle myself into the task at hand. We stop in a residential area where I have to carry out the emergency stop, perfectly done, then comes the U-turn. I think to myself, it’s just a turn in the road and remember what I have been taught. No ffot down and I complete the turn, perfect! We head of out onto the country roads getting up to around 60mph. Will he be able to keep with me as I take to the twisties.
40 Minutes later were back at the test centre. Moment of truth. A few questions and he tells me I’ve passed. You beauty. He hands me the certificate and I sit back and relax in the test centre until my instructor returns. A few moments later and with a big smile on my face I show the examiner my certificate. Congratulations!!
We ride back to the training centre with my next task at hand, get kitted out with the gear I need and purchase my first bike…
Wheels…
While I had been learning to ride, my instructor took me to various dealerships. Why? To show me all the different types of motorbikes available and probably to set me on the right road to parting with some hard-earned cash.
A favourite haunt quickly became the local Honda dealership in Grangemouth. The CB’s and CBR’s, the Fireblades, the cruisers and not forgetting those huge tourers. Admittedly it didn’t take me too long to settle on a chosen bike to spend my money on.
But what type of bike was I looking for? I wanted the looks of a sportsbike but also wanted the touring ability with a more upright sitting position. I came across a VFR800 Vtec, blue, clean and smiling back at me. It looked impressive, but was it for me? Can I help you, sir? Test ride sprung to mind but would they let someone who has just passed their test out on the open road with one of their bikes. Not a problem, Sir! Do you have your driving license? Of course, I did and the test ride was arranged there and then.
I had an hour to pass as they had to dig the bike out of the showroom, well it was surrounded by other bikes. I returned ready and raring to go. Here’s the keys, Sir. Take about an hour and we’ve put some juice in it for you. Sweet, suited and booted, off I went.
Honda VFR800 Vtec
It’s not long though before I become comfortable with her. I reach a long straight, the weather is dry and sunny, so I open up the throttle. In no time at all I am whizzing along, remember to look at the speedo and slow down, the Vtec kicks in and there is a sudden surge of power as all the valves kick in.
I cruise along full of enjoyment. Heading north towards Stirling now I take to some twisty roads. I’m not about to try and get the knee down but the handling of the bike going through the corners is just amazing. The sun beating down on a clear October day I am just simply loving every moment of this first little adventure in what would eventually become my pride and joy. The time seems to pass in no time at all and before long I am back at the dealership with a huge smile on my face.
Back in the dealership it was down to business. How much was it gonna cost me? What deals could I get? In the end it all sorted itself out the way I wanted it too and I left the dealership a happy man, and a little lighter in the pocket.
All I had to do now was tell the my lovely wife what I had just gone and done…
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