纳米小虫之家

2010年4月18日

High Speed Sync

从 Digital Photography Tips and Techniques 作者：picmax

If you have read our previous post titled Understanding Flash Sync Speed, you probably know what high speed sync (HSS) is. If not, or you need a refresh, read the post or watch this video instead. The following discussion of HSS may be a little too technical or detailed but the hope is to clarify some of the confusions I have seen in a few internet discussions.

Shutter speed

Shutter speed is a relatively easy concept to understand. It is the time the image sensor is exposed to the light coming in from the lens. However fully revealing the sensor takes time as the shutter travels at a limited speed. For most DSLR cameras, the sensor has two curtains, the front curtain opens first then the second curtain follows to block the sensor. The speeds they travel has to be exactly the same or the exposure will be uneven across the frame. Shutter speed of 1/250s means, exactly 1/250s after the first curtain starts to open, the second curtain starts to close. If the first curtain takes 1/250s to fully open, the second curtain has to close immediately after the first curtain is fully open. For a higher shutter speed, for example 1/2000s, the second curtain has to begin closing before the first curtain is fully open. That means the two shutter curtains will form a slit that travels across the sensor. At no time the entire sensor is fully revealed.

(Maximum) sync speed

The maximum flash sync speed is defined as the fastest shutter speed at which the entire image sensor can be illuminated by a single flash pulse. But how long is the flash pulse? There isn’t a standard and the flash durationalso depends on the flash power. The flash duration is the longest for the maximum power output of a typical Xeon flash. Typically it is about 1/1000s. If a camera has a maximum flash sync speed of 1/250s, the shutter has to take no more than 1/250s – 1/1000s = 1/333s to open in order to leave the entire sensor area open for the 1/1000s flash pulse.

It also means, you can sync a little faster than 1/250s if the flash duration is very short.

The next available standard shutter speed is 1/320s. If the flash duration is shorter than 1/320s – 1/333s = 1/8000s, you should be able to sync at 1/320s. At least, that is the case with my Nikon D200 and a SB-800 set to 1/32 power and triggered via PC port. Actually the black border is barely visible at 1/400s. With a eBay trigger, I can sync at 1/320s but 1/400s gives me a large black band. It is reasonable to assume there is some delay in the signal conversion and transmission process when a wireless trigger is used.

High speed sync

During high speed sync flash photography, the shutter still travels at the same speed but the sync speed is no longer limited to the shutter speed at which the entire image sensor can be illuminated by a single flash pulse. The flash provides a uniform illumination as the shutter slit travels across the sensor. Even though only part of the sensor receives the flash illumination reflected from the scene, on average, the entire scene appears to be illuminated by a uniform light source during the exposure.

A typical uncontrolled Xeon flash discharge does not give out even illumination. In order to provide the appearance of uniform light, the flash control circuits pulses the discharge at high frequency. The controlled discharge provides consistent light output during each pulse. The amount of light output is controlled by the pulse frequency and duty cycle (percentage of each period during which the pulse is on).

The following image (adapted from Nikon’s patent application US2002/0048457 A1) illustrates the aforementioned concept.

If you are curious about a real world example, here is a capture of SB-800 firing 1/32 power at 1/8000s. The period of the pulse is 20 microseconds. The pulse intensity does not actually have the square shape shown here. I used a logic analyzer that is a digital, not analog, capture device.

High speed sync hack

Not all flashes support high speed sync. Nikon SB-600, SB-800, and SB-900 support it. None of the Nikon DSLR camera’s popup flash supports it. Some third party flashes do not support it even through they may claim to be Nikon iTTL-compatible.

Some smart people have figured out a way to enable high speed sync for the flash that does not support it. Basically you need to mount a HSS-compatible flash on the hot shoe of the camera, then trigger your remote flashes from the PC sync port on the flash or the camera. When HSS is enabled, the trigger signal on the PC sync port is sent as soon as the shutter curtain starts to move, instead of after the first shutter curtain is fully open.

How could this work if the flash duration is only ~1/1000s while the shutter slit takes longer than that to travel?

The following is a discharge curve of a SB-600 at 1/1 full power. Clearly, the “1/900s” 1/1 flash duration in the SB-600 spec isn’t the time it takes to completely discharge the flash. The actual flash duration between the start of the flash to the point flash light is completely gone is quite long: ~1/125s.

This hack works to certain extent but the obvious problem is uneven illumination because the remote flash is still making a single discrete discharge. Sometime this may not be very noticeable if the subject takes up only a small area of the frame.

High Speed Sync

从 Digital Photography Tips and Techniques 作者：picmax

Shutter speed

(Maximum) sync speed

It also means, you can sync a little faster than 1/250s if the flash duration is very short.

High speed sync

The following image (adapted from Nikon’s patent application US2002/0048457 A1) illustrates the aforementioned concept.

High speed sync hack

How could this work if the flash duration is only ~1/1000s while the shutter slit takes longer than that to travel?

High Speed Sync

从 Digital Photography Tips and Techniques 作者：picmax

Shutter speed

(Maximum) sync speed

It also means, you can sync a little faster than 1/250s if the flash duration is very short.

High speed sync

The following image (adapted from Nikon’s patent application US2002/0048457 A1) illustrates the aforementioned concept.

High speed sync hack

How could this work if the flash duration is only ~1/1000s while the shutter slit takes longer than that to travel?

2010年4月5日

Wildlife Photography FUNdamentals

从 Beyond Megapixels 作者：Guest

有 1 人喜欢此条目

The following post was submitted by Kevin Ebi and you can see more of his photography here.

Photographing wildlife can be incredibly rewarding, but it’s also extremely challenging. Even if you’re lucky enough to find the animal you’re looking for, it may not be in the mood to pose for you. The challenging times are certainly frustrating, but they make you appreciate a stunning wildlife image all the more.

Here are some tips I’ve developed over the years to maximize fun and minimize frustration:

Get over your lens envy

I was a wildlife photographer for many years before I was able to afford a really powerful telephoto lens. And I may have been more successful because of that.

There are two types of wildlife images: the trophy shot and the story shot. Having a really powerful lens tends to make people go for the trophy, for example, an image where only the bald eagle’s head fits into the frame. Those can be impressive images, but they don’t tell you the story of the animal.

Images that show where and how the animal lives within the context of its environment can be even more stunning. You can create these images with any lens.

Read and study

The more you know about your subject, the more likely you are to make great images of it. My bookshelf is full of field and wildlife behavior guides. I not only find them interesting, but helpful.

Photography is about being in the right place at the right time . There’s always an element of luck, but by knowing more about your subject, you can increase the odds in your favor.

You don’t have to travel

I love being in a remote corner on the opposite side of the world, photographing animals that I normally don’t get to see, but I’ve also learned to appreciate the pond that’s 10 minutes from my house.

First, if I photographed only when I travel, I wouldn’t have much of a library. More importantly, the pond has taught me a lot about wildlife. Being able to watch the pond – and its residents – change throughout the year helps me learn more about nature than I could pick up in just a few weeks in some foreign location. And, again, knowledge provides opportunity.

Make friends

There’s no substitute for experience, but talking with the locals when you’re on the road can make up some of the difference. Talk to as many people who appreciate wildlife as you can. You never know what they’ll share with you.

In New Zealand, I met a woman who drew me a map to a secluded beach where an endangered type of penguin roosts for the night. I didn’t have to ask for that. Once she could see that I was passionate and respectful of wildlife, she volunteered the information. I never would have found that beach on my own.

Another time, while photographing sandhill cranes from the side of the road, I met a farmer who has burrowing owls nesting on his property. And he now calls me whenever he finds a new nest.

In the Mojave Desert, a ranger led me to a desert tortoise that was several hundred yards off trail. I ended up giving his group an image they could use in materials to protect the tortoises’ habitat.

Don’t get too close

This tip is for the safety of you – and the wildlife.

As the word suggests, wildlife is wild – unpredictable. Your camera and lens won’t protect you from charging bears. There’s a well-documented photography-related death in Yellowstone National Park. A photographer walked right up to a seemingly docile bison. It mauled him. Don’t be that guy.

It’s also not good for the animals. Especially during the mating and migration seasons, animals need to conserve energy. The energy that they expend fleeing from you may be energy they needed to migrate or to raise their young. No photograph is worth an animal’s life.

Kevin Ebi is a nature photographer whose images have been used in magazines such as National Wildlife and Outdoor Photographer, as well as books and calendars. He is a featured photographer in the book “The Wild Within,” which documents wildlife in the Seattle Arboretum. He sells prints and licenses images through his site. He shares photo tips at his blog, located here.

2010年3月24日

中国不做老大很久了。

中国要不要做老大？中国有没有做老大的决心？有没有信心？

在现代社会老大就是要创新，只有这样才能为中有才，无论哪里的才都可以啊。只有民智，才能充分发挥创造性，才能让中国制造变成中国创造。如民不智，我们还会受到压制。我们现在制造走遍全世界，与N年以前中国瓷器和丝绸走遍全世界有啥差别？会不会有第二次鸦片战争啊。

关于Google退出一直想写点啥，但是一想到****就是在无语。

当然一个公司不能狎啥令啥，但是至少需要一个公平公正的对待。我们反对超国民待遇，但也不能让稍有意见的人消失啊。

对谷歌的退出，你可以有不同意见，但是不要这么没逻辑

从零零发（赵某人刚）作者：llf

有 23 人喜欢此条目

共享者：

我很愤怒，不是因为g.cn的退出。关于Google的退出，实际上早在年前我们就多次讨论，并客观分析到今天这个必然的结果。
然而一些傻逼，没错，就是纯傻逼们，他们不需要理由，不需要分析，不需要逻辑，只要给他们一顶帽子，他们就能喷遍整个地球的人，从那时起，就开始了他们拙劣的扯淡、造谣和抹黑工作。
我愤怒的是今天扑面而来的这些扯淡、造谣和抹黑的言论。和30多年前毫无二致的是，政治正确依然是在很多人心里比良知和真相更重要的存在。在这个刚刚看完刘慈欣的《三体》的日子里，面对周边这样的环境，让我心情极度愤怒和低落，甚至一度在思考生存的意义。然而一个Twitter上的朋友点播了我。过去我总是不屑与傻逼争论，因为大家知道，那会让人们分不清谁是傻逼。但是我今天认识到得事情是，要打败傻逼，就要用于把自己降到傻逼的水准上去，用键盘和鼠标当武器，和傻逼们战斗。我不怕别人分不清到底谁是真傻逼，因为，总需要有人和傻逼作战。而且我和傻逼不一样的是，我和傻逼吵完架，我仍然可以回到我自己，做一个正常人，而傻逼，会继续，并一直傻逼下去……

有关G.cn撤离中国的来龙去脉，即使你用百度，也能找到更多真实消息。我这里就不说了。

今天那些关于故意抹黑Google的五毛帖，其实都是充满了自相矛盾和难以自圆其说的大字报式的胡话，很遗憾，此类言论往往对贵国那些“不明真相的群众”还特别有杀伤力。

这也是我，决定要把自己当成傻逼，来理论一下的原因。岂能因声音微小而不呐喊？！拜你们这些砖家叫兽还有那些五毛党所赐，现在的赞歌、粉脂、麻药还不够多吗？

五毛胡话1：Google在中国被百度打败，经营不下去了，所以要退出。

事实上是，谷歌中国用4年时间，将市场占有率做到将近三成，无论是通过Google的搜索，还是百度，可以看到在各个商业第三方调查机构的统计里面，谷歌在中国市场的占有率都超过了这篇文章给出的12.7%的数字。更无论，谷歌中国在中国仅有800员工，根据2009年的财报，其收入超过20亿元人民币，而百度同期收入为44.5亿，百度的员工是多少人呢？超过7000人！

通过以上数字，就算用大脚趾头想也能明白，谷歌中国在中国的经营不但没有失败，而且非常成功，其人均利润率更是大大超过了百度。就算相较于Google全球的240亿美元的收入相差甚远，这也只是因为整个中国市场的盘子大小问题，不是谷歌中国无法赚到钱。

五毛言论一方面断章取义，一方面虚构数据，试图让不明真相的群众在这些似是而非的数字中，以为谷歌是因为经营不善而暗淡退场。然而这扯淡的是，如果一个在中国在市场占有率第二，甩开第三名10倍差距，占据搜索广告收入1/3的的企业也真的如他们所说就“经营不下去了”，那中国的市场如何又向他们所说的“事实证明，中国互联网的投资环境、发展环境是好的。”

该文还说“我想谷歌只是在找个体面的方式来撤出中国。谷歌在中国的业务并不好，根本就斗不过百度。”这简直是滑天下之大稽。你能想象一个公司会对仅占其总业务收入1%的一个市场的“不够成功”（姑且按文内的说法，其实一点都不是不成功，上文提到，谷歌在中国的经营非常好）就要费尽如此脑汁来找“遮羞布”？在一个充满着躲猫猫、白开水、70码的贵国，你们见过什么事“遮羞布”么？

五毛胡话2：谷歌双重标准，内容审查在世界上都很普遍。

这又是一个试图依靠偷换概念混淆视听的手段让人们以为谷歌是别有用心妄图挑战中国法律，制造外国人在华特权的企图。

但是从1月12日Google的声明就说的很清楚，他们希望建立一个“在法律框架下做一个不过滤不审查的搜索引擎！”，这个当地不仅仅只中国，还只所有地方，他们希望每一个地方的产品，都能符合当地法律的要求，但是前提是，你得有这个明确要求，而不是今天打一个电话，明天发一个邮件说这个要屏蔽，那个要删除，还给不出任何理由。然而五毛党们对此避而不谈，对Google要求中的前置条件“在法律框架下”避而不谈，有意突出后半句的“不过滤不审查”，让对网络不熟悉的普通用户以为Google是要治外法权，这一点除了用卑鄙两字来形容，实在找不到其他合适的字眼。

这个时候，必须要借助一位被网友授予国际重大金奖的人物的一句话来评价：“这种卑鄙伎俩阻挡不了广大人民群众对真相的了解。科技的进步、世界的和谐是历史潮流，是任何力量都阻挡不了的。”

贵国政府总是声明，任何在中国经营的公司必须要遵守中国法律，好像谷歌的退出是要挑战这一底线一样，让五毛和小将们以及一些对互联网不了解的人们义愤填膺。但是事实上是，对于贵国的互联网审查制度，这个“法律”在哪儿？到底有没有一部或者一系列能够让每一个在互联网上的人能够看到的法律、法规、文件、规定、办法？明确的告诉我们到底什么是合法的，或者什么事不合法的？

没有一个透明的规章，人们就不能去遵守所谓的制度。政府部门高兴的时候可以说“我爱共产党”这句话是褒义的，在不高兴的时候可以说你在讽刺它。你只能无奈地对着屏幕喊草泥马。

每一个在中国做网站的大企业、小公司，甚至个人站长都知道，下面这个笑话，事实上真实的发生在我们身上：

半夜IDC急电，“你的网站有涉嫌台独的关键词，请立即删除！”站长立即从被窝里爬起，冒着零下10度的严寒上网，找那个违法关键词。最后找到的是这样一条信息：转让一台独立服务器。

其实关于审核，个人网站“可能吧”在《审查机器》一文中已经说的很明白了，Google本身就有对不良内容的过滤机制，同时也有针对更安全的搜索结果的safe search模式。（今天，可能吧因为另一篇关于Google的文章，可能吧被挡在了墙外，为了方便不便翻墙的网友，我摘录可能吧《审查机器》的部分内容如下）

Google之所以想退出中国，不是因为受不了审查制度，事实上Google很早就有Safe Search选项了，在Safe Search里，成人内容是被屏蔽的。
另一方面，Google也会在搜索结果里屏蔽那些有版权争议的内容。
那么，既然Google自身都在审查内容，它为什么反感中国的审查制度呢？
根本原因还是在于政策的不透明。
Safe Search是一个选项，用户可以自行关闭；当且仅当Google收到版权方的抗议，并证明某些网站确实存在侵权行为后才会屏蔽这些网站。这一切都是透明的。
图：Google Safe Search选项
而Google在中国，每天都收到通知要屏蔽这个网站屏蔽那个网站、屏蔽这个关键词屏蔽那个关键词，这些通知是没有规律可寻的，也没有法例列明。你要细问法例，得到的回答只会是“依法屏蔽”。
屏蔽色情是可以理解的，但屏蔽比如下面截图里的关键词就很难说出口了：
我一直都说，屏蔽色情保护未成年人是借口，屏蔽政治信息，让信息不流通才是中国的治国之道。

上面那张图里的文字很中国吧，“相关法律法规和政策”，就是没有法律法规和政策。我们都知道在贵国最强悍的部门是相关部门，你知道很多事情都是相关部门去管，但是你不知道谁管。法律也一样。其实每一个上过大学的人都知道在写论文的时候，如果你写到相关资料，一定要后面注明着相关资料来源于哪里哪本书第几页。我们的法院在判罚的时候，也不可能说xx犯罪嫌疑人因为违反了相关法律就入狱xx年，还要说因为什么法的第几条第几款第几项的xxxxx。而在互联网上，什么都没有，只有“相关法律”。我倒是想请外交部的发言人也好，国新办的发言人也好，还是工信部的发言人也好，或者什么其他“相关部门”的“相关人员”也好，你们每每厉声声明，要我们遵守相关法律，能不能有一次你们能不厌其烦的，勉为其难的，循循善诱的，谆谆教导的，仔仔细细的，条条款款的告诉我们，这个“相关法律法规和政策”，到底是什么？

哪怕你们就恬着脸说：“这相关法律法规和政策，就在我们脑子里”也行啊，我们也认命啊！只要你能说出来！

五毛胡话3：谷歌和美国政府有关联，他们退出是别有用心的

这是一个文革式的帽子口号，你做什么没关系，你是对是错不重要，关键是你的屁股坐在哪条板凳上。而且，更重要的是，你的屁股实际上坐在哪里也不重要，重要的是，我觉得你坐在哪里。

希拉里在1月7日请美国一些科技企业高管高管吃饭，成为了这些五毛党抹黑Google的另一个证据。这种搞笑的逻辑，让我一时无语，只想问问，那这些又算什么？如此看来，美国政府是不是应该想办法整一下腾讯？再就是阿里巴巴也不要做外贸了，谁让有那么多中国领导视察过他们呢？

……

——————-2010年3月24日0:47追加分割线——————–

五毛胡话4：谷歌是别有用心的，谷歌是炒作，谷歌是撒娇，谷歌是受人指使……

这一系列言论我们称之为“动机论”吧，就是谷歌一定是有某种动机的，而这种动机是不纯的，是坏的，因此，谷歌就是坏的，至少是有坏的可能，因此……因此什么？反正，和自己的错误就完全无关了。

这是五毛党搅混水方法的一个高级技巧，比如下面19楼回复就问道：“Google真的很难撇清。如果有人说‘Google放弃不到1%的全球份额来换取美国政府的某种特别支持，同时又能挣得名声’，怎么反驳这种说法？”（我不是说回复19楼是在搅混水，而是说这个问题是个搅混水的问题。）

这种说法，首先先是要假设美国政府就是反华的（哪怕是真的，他这句话的前提也是假设而已），然后再假设如果一个企业能够恶心一下中国就能过获得超过这个企业在华利益的美国政府支持，然后这个时候这句话完全忽略了这件事情本身是否牵扯到事情本身的真实原因——谷歌为什么要退出中国？谷歌声明里究竟表达了什么？而高级五毛们就以这种连续两个假设的动机，偷换概念当做了事情的“所谓真相”……

在这里许多回复中，你不发现，很多质疑或者反对我的人，已经完全掉到“动机”的坑里了么？

事实上，整篇文章，我只是在说一些中国政府做的不对的地方，我们反对断章取义的结论，反对真假参半的证据，反对不透明的黑箱审查制度，反对对互联网妖魔化的抹黑……我想做的，只是要反对这些错误舆论。

退一万步讲，就算Google别有用心，就算世界上充满阴谋，但是我们作为一个中国人，希望中国自己更好，更阳光，更正义，有什么不对么？

在你写出1+1=3，老师说你错了。这个时候你说：唉你看，那个谁还写1+1=4呢，我比他强多了！老师你批评我是不对的！

你觉得这不荒唐么？

——————-2010年3月24日0:47追加完毕分割线——————–

你还见到过哪些或者扯淡的，或者离谱的，或者似是而非的，或者驴唇不对马嘴的抹黑Google的言论、新闻、评论？请回复这篇日志，我们一起来以一批破！

btw:如果你觉得Google和百度之类的东西差不多？如果你并不是很理解Google为什么要（可以）不作恶？如果你觉得商业只有“坏”才能够成就利润？推荐你一定读一下这一篇文章：《Google百度和谷歌的那些事儿》

PS：关于什么是“贵国”，请大家点击查看来源。

2010年3月17日

Cloud Photography

从 How to Photograph Fireworks Displays 作者：Guest Contributor

有 54 人喜欢此条目

How to take advantage of what is right above you.

The sky is the single most abstract and dynamic canvas that a photographer has at his disposal. It is an endless source of inspiration that can change a boring photo into one of tremendous interest.

Sweet Home Under White Clouds - by tipiro

The sky is a key element in almost all landscape photos and if you can’t get it just right the entire photo will suffer. The problem is that it is often very difficult to properly expose the sky and the ground at the same time.

By turning to tools such as graduated neutral density filters or bracketing photographers have been able to perfectly expose photos right on the camera, however, this isn’t always possible given circumstance.

furthermore, the sky itself doesn’t always behave. Sometimes you show up for that shoot and the sky is boring and uninteresting. Other times the sky simply does not convey the right mood. Sometimes an image needs a new sky.

Shoot the sky when it is interesting

single Carry your camera everywhere with you and always make a point to look up to the sky as you go about your daily routine. If the clouds are doing something interesting. Take a picture of them.

Begin to create a collection of cloud photos that you save for later use. The clouds don’t have to always be wickedly cool or on a vibrant sky but it is important to build a diverse collection.

These photos, while often are interesting enough to become stand alone images they truly shine when used to augment something else.

Tricks to shooting great clouds

Make sure that you shoot more of the sky than you need. It is easy to crop in later if necessary.
Slightly underexpose the image. The sky is notoriously bright during the day. Overexposed clouds tend to look goofy. You can always fix up the exposure later in post processing.
Get creative, clouds are very abstract try interesting things with them. Long exposure times. Wild Filters. Go Nuts!
Watch out for things in the sky. While they can always be removed later it is annoying when a bird or plane is in the middle of your frame.

How to make certain skies more interesting

Even though the sky is almost always interesting to a degree, sometimes you want to make it that much more compelling. This can easily be done in Photoshop.

Cheery

cheeryclouds Everyone likes bouncy soft clouds. They can make a scene feel more fun and energetic. Cheery clouds are characterized by smooth white tones in the clouds set upon a vivid blue backdrop.

Energetic

energeticclouds Clouds can also look very interesting when given tension.

This can easily be achieved by framing the clouds at a unique and compelling angle.

Antique

antiqueclouds They have nearly become a cliche but they are also very effective.

Antique clouds can perfectly help frame all sorts of interesting photos. Antique clouds tend to be moody and work best in a more overcast sky.

Muted

mutedclouds You could also consider them boring clouds. However they are also very useful when you simply want to add texture.

Muted clouds are characterized by less bold lines and lower contrast.

Ominous

ominousclouds You can also add powerful emotion to a piece with more rugged and defined clouds.

These clouds tend to feel foreboding and can really add tension to a composition. Ominous clouds looks best when the clouds themselves have high contrast and often are very dark. Such as before a storm
.

From Above

cloudsfromabove Did I mentioned that you should take your camera everywhere?

This includes on an airplane. Clouds look really cool from above.

Getting Creative

stylizedclouds Once in Photoshop you can either let your clouds remain realistic or you can easily change them dramatically to add another dimension to their abstraction.

This will usually depend on the style of image you are aiming for in the final piece but given how abstract clouds are it is very easy to vastly change them without ruining their effect.

Don’t be afraid to really experiment, the worst possible outcome would be starting over but the rewards can be infinite.

Things you can do to clouds to make them more abstract

Add extreme color of any type. We are used to seeing clouds with sky blue as a back drop. They also look good with most other colors of the spectrum.
Give them movement. Add motion or radial blurs to simulate movement.
Warp them. Given that clouds have no predefined shape you can use tools such as liquefy to mold them to your desired shape.
Add things to them. Birds, rainbows, and lightning can all add an interesting twist.

You have shot your clouds… Now what?

Take advantage of them. As mentioned above you can’t always count on the sky to deliver it’s best performance when you are taking your pictures.

Next time you have a photo that you think could have been amazing but just isn’t quite right consider how it would look with a new sky.

Look through your collection of clouds and find the perfect sky to match your photo. Just make sure the sky you have chosen fits with the image you are giving it to.

Things to watch out for when adding a new sky

Make sure to cut out the original photo well. A halo of the old sky can look really weird.

Instead of completely replacing the old sky, consider blending it with the new sky to make things look more natural.

Make sure the lighting matches. It would look really weird if you add a sky behind a mountain with the sun in it but the shadows on the mountain imply the sun is behind the photographer.

Match the tones so that the entire image has similar saturation, brightness, and contrast. It needs to look natural.

Other cool tricks

You can vastly increase the size of the sky. For example, in the image above the original sky looked fairly good but it was cut off by the end of the frame. By adding a new sky I was able to use one that was much taller and thus make the picture more interesting with a taller aspect ratio.
You don’t always have to replace a sky. Perhaps you photo doesn’t have any sky in it. But it does have some water or other reflective surfaces. Create an interesting reflection.
Layer skies. If done well, and carefully, you can layer several skies together by blending them and create a compelling effect.
Transform them. Flip and rotate them. A sky doesn’t always look it’s best right off the camera. Find the angle that best benefits the final image.

Conclusion

Clouds are a great and fun canvas to work with. They inspire creativity and help expand your ability as a photographer. The greatest strength of the sky is it is endless in it’s abstraction and thus is only limited by your imagination.

8 Tips for Photographing Butterflies

从 How to Photograph Fireworks Displays 作者：Guest Contributor

有 42 人喜欢此条目

In this post, Steve Berardi from PhotoNaturalist discusses eight tips for photographing butterflies.

Photo by Steve Berardi

Butterflies are pretty sensitive little creatures. Get too close, and they’ll fly away in a hurry. And, even when you do get close, they’re constantly moving from flower to flower, gathering their most precious prize: sweet nectar. All this makes it difficult to photograph butterflies, but here are 8 tips for dealing with some of these problems:

1. Use a tripod, but keep the head loose

Butterflies move quickly from flower to flower, so you won’t have time to lock in your tripod. But, you can still use it for some stability by keeping the head loose (so you can quickly move the camera).

2. Wait for colder weather

Butterflies need heat from the sun to use their wings, so they like to take it easy when it’s colder out (early morning or late afternoon). With colder weather, you’ll be able to approach them more easily.

This photo was shot on a cold overcast day. The cold weather kept the butterfly from moving, and allowed me to position my macro lens just a few inches from the butterfly. (Photo by Steve Berardi)

3. Position your camera’s sensor so it’s parallel to the butterfly’s wings

You only get one geometrical plane of complete sharpness, so you want to put as much of your subject in this plane as possible. With butterflies, you’ll want their body and wings tack sharp, so make sure your camera’s sensor is parallel to them.

4. Wait until the butterfly is frontlit by the sun

Side lighting will usually result in a harsh shadow across the butterfly’s wings, and backlighting is always difficult because of flares. So, wait until the butterfly moves to a position where it’s frontlit by the sun.

5. Use a fast shutter

When you’re photographing butterflies, three things are almost always moving: the camera, the butterfly, and the flower it’s perched on. To help freeze the action and increase your chances of getting a sharp photo, use a fast shutter by increasing your ISO to 400.

6. Shoot in JPEG mode (sometimes)

If you’re having a hard time with the wind and a constantly moving butterfly, you may want to consider shooting in JPEG instead of RAW. This will allow you to snap a lot more shots in a burst, increasing your chances of getting a sharp photo (when everything stood still for a microsecond).

7. Wait for butterflies (patiently), don’t chase them

If the butterflies seem extra sensitive when you’re trying to approach them, then try to just wait patiently at one flower instead. Although butterflies will usually get scared if you approach them, they’ll usually land on flowers right next to you if you’re already sitting there. Be patient though: it might be 15-20 minutes before a butterfly shows up.

8. Be careful not to cast a shadow on the butterfly

Butterflies love the sun, so if you cast a shadow on them, they’ll usually fly away. Remember this as you’re approaching them.

What did I miss?

If you have another tip for photographing butterflies, please share it by leaving a comment below! Thanks!

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2010年4月18日

Shutter speed

(Maximum) sync speed

High speed sync

High speed sync hack

Shutter speed

(Maximum) sync speed

High speed sync

High speed sync hack

Shutter speed

(Maximum) sync speed

High speed sync

High speed sync hack

2010年4月5日

2010年3月24日

2010年3月17日

How to take advantage of what is right above you.

Shoot the sky when it is interesting

Tricks to shooting great clouds

How to make certain skies more interesting

Cheery

Energetic

Antique

Muted

Ominous

From Above

Getting Creative

Things you can do to clouds to make them more abstract

You have shot your clouds… Now what?

Things to watch out for when adding a new sky

Other cool tricks

Conclusion

1. Use a tripod, but keep the head loose

2. Wait for colder weather

3. Position your camera’s sensor so it’s parallel to the butterfly’s wings

4. Wait until the butterfly is frontlit by the sun

5. Use a fast shutter

6. Shoot in JPEG mode (sometimes)

7. Wait for butterflies (patiently), don’t chase them

8. Be careful not to cast a shadow on the butterfly

What did I miss?

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