Image sharpening using High pass filter

With Photoshop, a photo can be sharpened in many ways. Some popular among them are : sharpen, smart sharpen and most popular unsharp mask. Here, I wish to demonstrate image sharpening technique I use : using a high pass filter. Its a few step process and creating action for this one is also fairly simple. Once created action, sharpening can be applied with just a click to any image in future. However, I wont be explaining here how to create actions, some other time.  :-) OK, so lets begin.

Step 1. Open the image. (layer name: background, by default)

Step 2. Duplicate the image. (layer name: Layer1, by default)

Step 3. Change the blend mode of Layer 1 to "Overlay". Blend modes can be found just above the layer panel.

Step 4. Now apply High pass filter to Layer1. Its can be found under the menu : Filter - Other -High pass.

Step 5. Set the radius value around 5. The key for correct sharpening is that one should see the edges in the thumbnail. press OK.

Step 6. Now, adjust the intensity of sharpening just by adjusting the Layer1 opacity.

Step 7. Cheers !

The images here are for demo. Changes may be  subtle to observe with images provided. Better, open them in separate window and compare them to see the effect. Ideally, advised to carry the high pass sharpening to ur own image with good resolution and observe the effect.

Before Sharpening, Butterfly species : Pea Blue

After sharpening

Few reminders:

1. Better original image provides better flexibility.
2. High pass filter improves contrast a bit.
3. This technique is well suited for photos with blurred background. As such background do not have edges, high pass filter is not applied to that part at all.

Photographing Butterlies - Camera Operation

   

In this post I am discussing some camera techniques explicitly to shoot butterflies. I assume the objective is to get clear, sharp and completely focused object and not discussing how to shoot an artistic shot. 

1. Mode of shooting: A good butterfly photograph should show sharp, entirely focused object with blurred background. To accomplish this, one has to choose aperture and shutter speed wisely. Here I assume ISO 100/200 (we will talk about it later). To shoot such images, aperture may be varied between 5.6 to 16 depend upon light conditions. Shutter speed and aperture acts opposite to each other (Higher f-number, lower the shutter speed). Having said this, if one is firing fill flash, shutter speed is restricted to synchronizing speed (normally 1/200 or 1/250). Thumb rule for shutter speed selection says: Shutter speed should be more or equal to the focal length. For example, when shooting with focal length = 200 mm, shutter speed must be at least 1/200s.This is important factor when selecting lens for photographing butterfly. Aperture will decide the depth of field. Simply say how blur is the background or what part of the frame is focused. Higher the aperture (say f2.8) more blurry the background. 

           With this little theory, lets come back to mode of shooting. Here modes under consideration are Manual, Aperture Priority and Shutter priority. I prefer to shoot in manual mode. This allows to select  shutter speed and aperture independently.  If sunlight is enough, I can achieve perfect exposure with many combinations of shutter speed and aperture. When, aperture/depth of field is priority shoot with aperture priority mode. This fixes the shutter speed. Sometimes shutter priority is preferred to shoot fast moving butterflies ( Mormon), Where continuous fluttering of their wings need to be frozen in the frame, higher shutter speed is necessary (Often 1/500 or above). Two images of Leafblue, are the example towards changing f number and its effect on depth of field. With f5 and descent sunlight I was able to achieve very good Bokeh and descent speed of 1/250. It was limited by synchronizing flash speed as built in flash was used.

As shot, External flash failed to fire.

2. Shoot RAW photos: RAW is just like digital negative of the photograph. It preserves every details and enables user to manipulate them in post processing. Whereas when saved directly in JPEG format, most of the data is lost irreversibly, and nothing great can be achieved in post-processing. Shooting in RAW is very much useful in situations where flash does not fires, achieving perfect exposure is problem (White or Violet surfaces), etc. Every SLR has an option to shoot in RAW and NOT every point shot have it. The only disadvantage RAW shooting offers is that it takes a lot of space. Size of RAW file is approximately 3 times larger than corresponding JPEG image.A typical 8GB card will hold around 300 12-bit RAW images. But one can always carry multiple cards and change them when required.

3. Flash: Always us Fill flash for butterflies, yes even in day light. I prefer to use fill flash always and adjust the shutter speed and aperture to adjust the blending of the fill light. This blending is important otherwise it looks like one has pasted the object into. If one is operating camera in aperture priority mode, this problem is solved by i-TTL facility. It selects amount of flash needed to be casted for perfect exposure, sensing the ambient light condition.

After adjusting exposure of the failed image. 

4. ISO: In simple sense, this is the measure of sensitivity of the camera towards light. Higher the ISO, higher the sensitivity, higher the noise. Generally ISO is setting is not changed in the field. For butterflying on particular day, start with ISO 400 (early morning upto 7am), then gradually start reducing ISO to 100 (at around 11 am in the summer). Obviously this depends on the ambient conditions. In shade, ISO might need to be increased again. So my advice to avoid all this jugglery, one can set ISO 200, a small compromise with noise and achieve maximum shutter and aperture.

Note: All images are copyrighted. (c) Paresh Kale, 2012.

Camera and accessories selection for macro photography

This post is about the camera and lens selection, particularly for shooting butterflies and flowers.

Lens Selection (For SLR):
This is really dance on the tight rope.
1. A macro lens at least 90 mm, with 1:1 reproduction. Lenses from 90 mm to 105 mm are handy lenses with descent minimum focus distance and focal length. 180 mm lens are bulky, costly however produces good bokeh. A 300 mm lens with VR will also serve fantastic overall. As it do not create 1:1 image, may face little problem with very small ones. This focal length will give nice bokeh and can be used with 2X TC for birding if fast enough.
2. VR/OS/IS is must. Image stabilization or Vibration Reduction technology increases the possibility of sharp images. VR I is sufficient. This lenses comes with more money obviously.
3. Internal focusing (IF) allows the focusing without changing the length of the lens barrel.

Camera selection:
 Many asks which one is better, Canon or Nikon? I say both are good, depending what kind of use u wish. Nikon has great low light capture probabilities. Canon can shoot good video. Canon 1D is famous in Hollywood for supportive shoots. For butterflying any of them will do. Here is the list of characteristics a camera should have to shoot macro photos.
1. Raw shooting ability.
2. Manual, shutter priority and aperture priority mode.
If SLR, then I would prefer to have at least a semi-pro body (Nikon D90/D7000 or Canon 60D/ 7d). Major advantages with this category is the built in motor.

If one is not using a SLR then,
1. Zoom around 12x to 18X is sufficient.
2. 12 MP is sufficient.
In this category I have seen pretty good results with Panasonic Lumix FZ series. 

Accessories selection:

1.  Battery: Cameras like D7000 can deliver upto 1000 snaps without flash/external flash. So for a short trip I dont see necessity of carrying extra battery. Even same would be the case with canon 60D or 7D. However, batteries of point and shoot camera exhausts after about 250 snaps. In that case one may need extra one or in some case two batteries per day. Better to go for original batteries. In case of extensive use of the batteries, non-branded batteries can give good returns on money invested. 

2. Flash: External flash is indeed necessary. It reveals true colors, tinges and hues on the butterfly body. Built-in flash is not sufficient for this. I have not yet used ring flash or R1-C1. But from the results people are posting, they seems to add more drama and story to the image as compared to external flash. Obviously a charger and rechargeable cells for external flash. Duracell batteries seems to last ling than most other n the category.Ranges from 5000 to 30000 RS or more. Branded ones are advisable as they provide i-TTL operation.

3. Tripod: Tripod wont be that useful in the field shooting last stage butterfly. It is useful when shooting early stages  like egg, larva. Buy a strong tripod with ball head. Cost may be from 8000 to 20000 Rs and more. Cheap tripods without ball head are difficult for operation, doesent take gear weight, shakes even with breeze. To remind, wind is the worst enemy for macro photography.

4. Storage: as I said Raw shooting is better. To do this, one needs more storage. Fast cards with data transfer rates above 30 mbps or more would be helpful. Cards in "Extreme" category, has such writing speeds. Also they have lots of protective feature against shocks, X-ray, water etc. Better to invest in them once. Also dont use card more than 8GB (optimistic value, most will suggest 4Gb some 2GB even). This slows down the writing process. 

5. Extension tubes: Will serve excellent if the object is static. One can be very near to the object and get very good magnification. Absence of any glass material, so doesn't cause any optical loss. Comes for about 8000 Rs. Kenko is good brand. My anticipation is, when used with lens like 50mm f1.4, can give sharpest results, competing even a macro lens. The disadvantage is the operation. Many times time needs manual focusing. Which makes it difficult for shooting moving objects. 

6. Tele-converter: Its a lens, with ability to magnify picture by 1.4X, 1.7X, 2X times. Also modifies the magnification in the same ration i.e. 1:2 lens will be 1:1 with 2X TC. Costs around 10,000 Rs. As it has glass elements, optical quality reduces. Useful with fast lens (aperture at-least 2.8 or so). Better to invest in some good lens than mounting this with other cheap lens. Not advisable.

Blue Oakleaf

  

Blue Oakleaf - Open wing position

    Blue Oakleaf is an unusual shaped butterfly, known for its unparallel camaflouge technique. When closed, the wings of the oakleaf simulates shape of a dry leaf. Seating position , normally on trunk or branch of the tree, adds drama to it and looks as if a leaf of the tree. Blue Oakleaf settles in such position, blends with tree structure and makes it a challenging to find it out when one was not tracking it.

Quick Facts:

Common Name : South Indian Blue Oakleaf

Latin Name: Kallima Horsfieldii

Typical Wingspan : 85 to 120 mm
Geographical Distribution : Mumbai, Nashik towards south.
Status: Locally Common

Different individuals of Blue Oakleaf
showcasing variety and uniqueness of patterns

    However in flight, this beauty is easy to identify. Flashy blue, quick but erratic flight and large wingspan features makes it easy for ID. In IIT campus, this insect was abundant soon after rainy season. A sure shot sighting on a bamboo tree sap in hill side area. On every visit, we were able to spot at least 2-3 specimens. However, any other activity by it like mating, egg laying, courtship etc was never observed by us. Surprisingly, oakleaf population seemed declined in February. Not a single specimen was sited.

As far as geographical distribution is concerned, This  specie is restricted to South India, hence named, and is not yet recorded in North India. Likely upper boundaries are Mumbai and Nashik.

  Most interesting fact about this species is its under-wing pattern. According to Winter Blyth, no two oakleaf bare similar under-wing pattern, making every individual unique. A collage of different specimens recorded in and around Mumbai will suffice this fact.

Hasora badra (Common Awl)

This is a beautiful skipper. It is very swift in flight. Its flight is long sustain. It is to be seen most often during early hours of morning and evening.

This skipper was first seen nectoring on Lantana in month of October 2012, in our campus. I was seeing this beautiful butterfly for the first time. It was around 8.30 in morning. It was lucky day because I decided to take camera with me, consequently got few snaps. I saw both female and male nectoring. Female have yellowish spots in the cell and in apical region of forewing while male has no yellowish spots on forewing cell and apical region.

Flash reveals purple colour on underside of their wings. There were 5-6 Common Awls. After that I regularly saw Common Awls nectoring there for almost 3 weeks.

Its status is given as 'not rare' in Wynter-Blyth.

Reference:

Wynter-Blyth, M.A. “Butterflies of the Indian Region”.

Charaxes athamas (Common Nawab)

This butterfly belongs to the aristocracy of the butterfly world. It can be seen in our campus. It is not very easy to see this beauty  because of its strong flight and habit of basking high on tree tops. But it is attracted to rotten food (fish, crab etc) and come to damp patches. So if you are willing, you can allure it with rotten food. It will not only attract Common Nawab but also many more attractive butterflies viz. Tawny Rajah, Black Rajah, Gaudy Baron to name a few. I saw it sipping tree sap once in the campus.

Paresh Kale and I first encounterd Common Nawab quite unexpectedly. One weekend we were casually walking along Lake side road. We saw on Acacia sp. empty pupa. It was more or less rounded, stout, short, hanging by single attachment with no body band. Some red spots were visible just above the wing case and rounded 'dots' on head. It was about 3 feet from ground. We realise that we got something “unusual”. In our excitement we search plant meticulously (thanks to plants small height ~ 6 feet). To our great joy we found green caterpillar with yellowish green V- shaped bands on its body and four horns on its head. It was resting peacefuly on silken bed woven on upperside of leaves. Later we found out it was mature and it pupated within few days. Beautiful butterfly emerge around noon after 8 days of pupation.

After that we (Swapnil, Paresh and I) saw Common Nawab around the same spot frequently  at ~ 12 noon. We saw female lying an egg on upperside of a leaf. The egg was yellow in colour and rounded in shape. At a time as many as 4 caterpillar were seen on the plant. So it was really common after all in IITB campus. It was also seen egg lying in Nagala block. It is more frequently seen than Tawny Rajah and Black Rajah.

Contributors: Paresh Kale, Swapnil Lokhande and Abhay Soman.

Pupa of Common Nawab

N.B. We saw Nawab (which one?) saw laying egg on underside of a leaf of some Gulamohar type tree, near Staff canteen. But unfortunately we didn't get its life-cycle.

Egg of Common Nawab