Tuesday, July 9, 2019

Let’s Shoot Against Light !




Capturing backlit subjects, especially those with rim light  always fascinate photo-enthusiasts, but  at times photographs of subjects  like birds requiring details disappoint photographers because despite their best camera settings they get  objects like dark patches against bright background.  Similar is the case of shooting birds in flight or against bright sky. Some photographers try to resolve these challenging issues by altering their camera settings. They either change ISO sensitivity, shutter speed or aperture and there are others who blame their equipment for poor performance. There are many others who do not find it necessary to go through the camera manual.
Although exposure is an issue of personal choice yet the bird photographers are advised to shoot birds with sun to their back. This is a good suggestion, but the fascination for backlit subjects inspires them to continue experimentation with their gear. The solution to this challenging situation of shooting against bright light lies within their camera. When we set exposure (a combination of Aperture, Shutter Speed and ISO Sensitivity), camera  evaluates whole of the frame and we get its average. In fact, we do not always need metering for whole frame. That’s why the camera manufacturers have devised different settings for metering. Therefore, often spot metering is recommended to shoot birds against bright light and centre weighted metering for birds in flight. Also, Auto Exposure Lock (AEL) can help in controlling the variation in exposure, especially when we have to shoot birds against bright sky. The AEL  can be used while reframing the image and prevent the current exposure from changing. Each metering mode has its specific functions.The choice for any of the above mentioned measures  depends on one’s liking and intensity of available light.
Apart from this, the challenging situation can easily be dealt with a small button bearing  EV +/- (Exposure Value ) and generally designed on top or the camera. Its commonly known as Exposure Compensation. This small feature has the ability to override the camera settings of semi-auto exposure modes, like Aperture Priority, Shutter Priority or Programme. In simple words, EV +/- is used to alter exposure  so as to make photographs brighter or darker. Its not necessary that by setting exposure we shall get desired result. Therefore, exposure compensation plays a vital role in further guiding the camera in meeting requirement of a photographer.
In case of Aperture Priority mode we select aperture of our choice, but camera automatically sets shutter speed. When we change  exposure value in this mode, it automatically changes shutter speed. Similarly, in Shutter Priority mode, we set shutter speed of our choice and exposure compensation automatically changes aperture. In manual mode its entirely up to the photographer  to set exposure and in Auto Mode exposure is set by camera itself. The EV does not function in full Auto and Manual shooting modes. In Programme mode, it depends on camera to either change aperture or shutter speed so as to give us desired result. Therefore, the significance of exposure compensation cannot be ignored and it should be used wherever required to get exposure of our choice.
Those who take photographs with Digital Single Lens Reflex (DSLR)  cameras,  can immediately check the results in camera  monitor  after  taking a test shot  and set  the exposure  value, if required. On the other hand, those who shoot  with mirror less cameras, have the distinct advantage to directly set the desired exposure value without reviewing any test shot in the monitor. As we compose the image and increase or decrease the  exposure value, the preview in the monitor enables us to see the changing brightness or darkness and how would be the final  image.

--Subhash Sapru
Hon Excellence USPA, APSA, PPSA, AIIPC

How to photograph flying birds




“How to photograph birds in flight”, sounds exciting and simple, but its  challenging. The advancement in technology has made it easy for photo-enthusiasts to meet such challenges  with ease provided they understand their photographic gear.  To make photographs of birds in flight, we need a camera and a long lens plus the ability to acquire focus on the subject with lightening speed. But first how to hold a camera if you are not using a tripod. Learn to be steady. The built in stabilisation and vibration reduction technologies do help, but we should not depend too much on them. While  handholding the camera, try to get support  to be steady or lean against a wall or a tree or a nearby vehicle. To maintain balance, stretch your legs and keep your feet as wide as is the width of your shoulders, slightly bend your knees, right hand should firmly hold camera body and keep your left hand below the barrel of the lens. Both the elbows should touch the chest and keep your eye on eyecup to view through the view finder. Such habits help in critical situations not only in bird photography, but even others. I remember having photographed the magnificent Multnomah Falls in Oregon in low light using the same technique, but there I had also stopped my breath to avoid any shake. It became a life time experience of having  captured 611 feet tall roaring Multnomah Falls.
          One may begin with a DSLR and at least a 200 mm lens. For many its convenient to photograph flying birds with hand held camera. Therefore, their camera and lens combo is light enough to enable easy mobility to photograph birds in flight. Those who use heavy long lenses and camera bodies having considerable weight are advised to use tripod with gimbal or ball head.
Its always good to shoot flying birds  preferably at your eye level with the thumb rule of keeping eye of the bird in sharp focus. This needs good tracking of the subject which can be achieved with continuous focus mode. Some cameras   offer auto focus  area modes. If your camera does not have continuous focus mode or 3D tracking, you may apply sports action mode, if it has. You may set centre weighted or spot metering and auto ISO.
 Those who make images with high resolution cameras and longer lenses, should be careful as these  may magnify simple  shakes or motion blurs in your images. While focus issue will blur the subject, camera shake would  blur the image  in one direction. Remember the thumb rule which states that the shutter speed should not be less than  the focal length of your lens. If you want to isolate your subject, keep the aperture wide open. While capturing birds in flight, the keen birders very well understand the approximate speed at which birds of different sizes fly. On an average , the shutter speed should not be less than 1/1600 sec. However, it depends on your preference to freeze the birds with shutter speed as high as 1/8000 sec or show motion of  tips of wings by shooting at low  shutter sped.
          Its not necessary that you always need fast shutter speed to capture birds in flight. Those who have practiced panning on moving subjects, can use it while capturing birds in flight. The basic fundamentals of shooting birds in flight are tracking and panning. First focus  on the subject with central focus point or a group of focus points depending on your choice, press  the shutter button halfway down , continue to keep your eye on the subject  through the viewfinder and track the bird’s flight path by keeping it in the centre of the viewfinder. Your lens may constantly adjust  the focus. In case the  bird moves out of camera frame, try to reframe it. As the bird or flock of birds  fly  from one side of the frame to the other, move your body and the camera in the same direction, but maintain your balance. Maintain visual contact through the viewfinder at all times. Its not necessary that everything is sharp in such images. Practice can give you better images. Therefore, practice, practice and practice. I am of the strong opinion that keen birders observe that the bird who dares to fall, is the one who learns to fly.
          While shooting birds in flight, we often observe that flying birds quickly move through different light conditions. Therefore, its advisable to photograph them in RAW. Also, do not forget to check direction of the sun and that of the wind. Preferably both should be behind you, but this may not be always possible. Also, remember the golden rule of keeping the eye of the bird sharp. The whole frame may not be sharp from corner to corner, but the bird should have acceptable sharpness. We can also photograph in overcast sky and low-light  by adjusting camera settings accordingly.
          Take-offs and landings of birds against light , especially in water bodies make artistic  images.
          The flights of birds can be erratic and they can change direction any time.  Therefore, we have to  compose the flying birds with a lightening speed while anticipating their movement. Prefer to track your subject through the viewfinder  and not the Live View. View Finder makes it easy to move or control the camera. While composing ,try to  keep negative space towards the direction the birds are flying.

Subhash Sapru
Hon.E USPA, APSA, PPSA, AIIPC

                       


Different, not Better


      
The master of candid photography, Henri Cartier-Bresson had described the camera as a sketch book, an instrument of intuition and spontaneity. This emphasises the need to understand our photography gear, know its strengths and weaknesses  so as to master its operation.
          Before buying a Digital Single Lens Reflex (DSLR) camera, many photo enthusiasts keep questioning  which way to go. Full frame or crop sensor  and now their attention is also drawn by the mirrorless camera. I think its better not to discuss the mirrorless for the time being as for many the choice is already confusing.
          The terms crop-sensor and full-frame refer only to the size of the imaging sensor inside a camera. The full-frame sensor is of the same size of a piece of 35mm film, the 24mm x 36mm format. On the other hand, any size of sensor  less than 24X36 mm is called crop sensor. It is also known as the APS-C,(Advanced Photo System). For instance, Nikon’s  full frame  sensor  is of 24X36 mm and the camera is  categorized as FX. Its crop sensor (camera body categorized as DX) is of the size of about 24 X16 mm. The crop factor is 1.5 x. Canon’s cameras  are also of full frame and those of crop sensor have crop factor of  1.3x and 1.6x.Other camera manufacturers also make crop sensor cameras, but their sizes differ.
Both the crop-sensor and full-frame cameras have their own advantages and disadvantages. For instance, in case of a crop-sensor camera of Nikon, the angle of view of a 50 mm lens  will be 75 mm whereas on full frame sensor its effective focal length will remain unchanged. Today, the high-end crop sensor cameras have the potential to provide image quality similar to that of a full frame. But it’s very difficult to point out the difference because it is simply negligible. Thanks to the improved sensor and processor technology.
While most of the sports  and wildlife photographers as well as photojournalists prefer crop-sensor camera to get an extra reach, the landscape and architecture photographers opt for full frame because of its potential to cover wide area. A crop-sensor camera can achieve similar wide view with a wide angle lens made for a crop sensor camera.
The question is, if now the gap between the image quality of both kind of cameras is negligible, why the photographers still feel they would upgrade to a full frame camera. It was in early 2000s that DSLRs began to replace film based Single Lens Reflex (SLR) cameras. The initial DSLRs used to have cropped sensor as it was not easy to make full frame sensor because of its high cost. Later on some camera manufacturers began to manufacture full frame cameras based on the standard 35 mm film format. We have among us many photographers who have enjoyed making images with medium format or large format cameras and the availability of full-frame camera is a boon for them. The crop sensor being smaller  than the standard 35 mm film format , was  considered as an a downgrade.
Practical Implications
Size-The basic difference between the two is of the size of the sensor as a result of which the camera body size also differs. The crop sensor camera is smaller in size and lighter in weight  whereas the full frame camera is bigger and comparatively heavier. Its not that the bigger sensor increases the weight of the camera, but the sensor size increases the dimensions of the camera body  and so makes it comparatively bigger and expensive. The lenses of the full frame camera are also bigger, heavier and expensive.  
The size of the camera  sensor makes interesting effect on various aspects like ISO, depth of field, apparent focal length of lenses and dynamic range, but this does not make us judge how good or bad a camera is. They are different. 
ISO : Higher the number of ISO, greater is the sensitivity of sensor. However, all digital cameras have base ISO which   can be 50 or 100 or 200. Today, most of the crop-sensor cameras significantly outshine their forebears from just a few years ago when people did not like to shoot even at ISO 800 or 1600. The facility of Auto ISO is a remarkable addition.
A full frame sensor provides high ISO and better low light performance, a broader dynamic range and yields a higher quality image as compared to that of a crop sensor. Thanks to the ongoing improvement in technology as nowadays even some of the latest crop sensor cameras are capable of high ISO performance.
Depth of Field: Remember the bigger is not always better. Depth of field  is defined as the zone of acceptable sharpness, which is in front and back of the subject in focus. It can be shallow or deep. The sensor size affects apparent depth of field. When shooting full-frame we get the benefit of a shallower depth of field, which is often liked by the portrait photographers. Those engaged in architecture and landscape photography also prefer full- frame cameras because that gives them wider field of view.
Focal Length: It is not a measure of how long or short  a lens is physically, but it is the distance in millimeters from the optical centre of a lens to the imaging sensor when the lens is focused at infinity.
If a full frame  and a crop-sensor DSLR take the same image from the same distance, with the same lens and point of view, the crop sensor camera will capture a tighter field of view than the full-frame camera. The focal length measurements of lenses being based on 35 mm standard, a crop sensor crops out the edges of the frame, which effectively increases the focal length.
Dynamic Range- It is the range of value between light and dark areas. We see wide range of intensity levels in real scene ranging from direct sunlight to shadows. Because of larger pixels, full-frame cameras  have a broader dynamic range in general, making them better equipped to capture the full brightness range of a scene that features both extreme areas of dark shadows and bright highlights, as well as mid tones. 
Many photographers like to shoot landscapes with a full frame camera because they need maximum wide area in the frame, leave aside other factors. However, when one is to choose between  the two for landscape photography, the answer is, "It’s your choice." Just to ponder over the issue, if one wants to have maximum depth of field for landscapes, it can be achieved with a crop-sensor camera. Also, while shooting at  the same angle of view, on a  crop-sensor and full-frame cameras, if the aperture is f/11 on crop-sensor one may have to use f/16 on a full-frame  to ensure sharpness from foreground to background.
          All said and done, no doubt the full frame camera will yield images of higher resolution  and would  have better low-light performance, but at a considerable price. On the other hand, the crop-sensor camera will help in achieving extra reach at a comparatively low cost. As Nikon has retained  “F” mount for its lenses for both kind of cameras, the full-frame lenses will work properly on crop-sensor cameras, but the reverse has limitations.
Today, many photo-enthusiasts remain keen to upgrade to full-frame with the hope to improve their image quality. But this assumption is not necessarily true. As said earlier, advancement  in  technology   has  narrowed the gap between the image quality and noise levels between full-frame and crop-sensor cameras.
In full frame cameras, the sensor space is used to make each pixel bigger. For example, a full-frame camera with 24 megapixels has bigger pixels spread over a larger sensor area than a crop-frame camera with an equal number of  megapixels. Bigger pixels absorb more light photons, which increases dynamic range in the photo. Greater dynamic range means there will be somewhat more detail visible in dark areas, and less noise. Therefore, better performance in low light.
Here a word of caution. Its not only the high cost, size and weight of the full-frame camera that matters, but also the care with which the images are made. Resolution of most full-frame sensors is so high that it exposes any shortcoming in technique and clarity of image. Thanks to the advancement in technology, none of the full-frame or crop-sensor camera is better, they are different.
          Now the camera manufacturers are   competing with each other in adding more pixels to their megapixel cameras. Is it a  marketing gimmick or do we really need so many pixels. Its high time for the photographers  to  be conscious of  possible compromises, if any.
Subhash Sapru
Hon.EUSPA,APSA,PPSA,AIIPC