Profil de JingyeDéjà VuBlogListes Outils Aide

Blog


22 avril

Macro (Closeup) Photography


0.005sec (1/200); f/13; Focal Length:105 mm; ISO Speed:640;Exposure Bias:0 EV;Flash fired; using 12 and 20mm extension tube
 
Received Kenko extension tube set this week. Today I have a play with it.

My favourite subject is ladybird. Though very small, it is a very beautiful beetle with bright red shell doted. The size–about 5-7mm-presents a serious challenge.

Back earlier April, I used Macro function comes with the lenses on Macro photography, which can be manually focus (with moving camera back and forth) at around 0.45m distance. The finished shoots after crop, zoom and interpolation become blur at edges. This is understandable-the finished photo I used as desktop is actually 4 times the life size by digital up scaling.


0.005sec (1/200); f/9; Focal Length:105 mm; ISO Speed:100;Exposure Bias:0 EV;Flash No; Using Macro function
 
It must be optical enlarge to solve the problem properly. There are few solutions around, such like use reverse ring to mount a 50mm lenses reversely. Use a bellow or an extension tube. Each solution has its pros and corns.

Reverse ring is the cheapest solution; you can pick up one from eBay for around 5 pounds including postage from China. It exposed the lenses inside out, could be a hazardous. And of course you lost TTL metering and auto focus.

Bellow is the most flexible but quite bulky. It takes a platform with ruler and guiding rails. I feel it is not the best choose for field shooting. I saw one on eBay going for £160 with a compliment 50mm FD lenses. A new one without lenses shipped from China costs about 30 pounds includes p&p.

That leaves candidate extension tube. By mounting it ( or combine a few and) to camera body, then mount lenses to it, you have the balance of flexibility, portable and lenses protection.
There are two types of extension tubes around. The economy one costs around £10 pounds, it doesn’t come with electronic contact points, so the camera and your AF, TTL lenses are disconnected. The one I brought from Kenko come with build-in contact points, it relays the communication between lenses and camera body so retains TTL metering and auto focusing. It totally costs 55 pounds from HK. About the price I paid for a 50mm 1.8F prime lenses. Consider there is no lenses, no motor and no circuit board inside but 3 aluminium rings, it is quite expensive.


shown with 12, 20 and 36mm extension tube mounted
 
Anyway I am quite excited to have a new gadget under my belt.

Global warming speeds up this Spring. Back three weeks ago there are a lot of ladybirds around our garden, now they all seemed go away. So it is very lucky I found a fella basking sun in the grass.

First I mounted a 25mm tube and set our little friend to tulip leave. Didn’t use flash as the sunlight was still very strong. Auto-focus is usable, but not very useful as the field of depth is very shallow regardless aperture: a little motion from the subject will mean refocusing. And the auto focusing is just not fast enough to cope. The strong wind didn’t help neither. With the enlarge effect from the tube, it renders subject violently movement.

After a few attempts, I retreated. I took my little model with the stem he is resting on and set the shooting studio.

I use flash mounted with diffuser. First I try 25mm, then 25mm plus 12mm and finally 25mm plus 12mm plus 36mm. At the beginning and didn’t bother to set up tripod, thinking with speed at 1/200 and image stabiliser, it should be alright without – I was wrong, later I checked the photos and found there are some compromised on quality.
As all three tubes mounted, the exposure factor increased to 6.1 for a 50mm lenses. I zoomed to around 100mm so the shake from the hands were even apparent. So a tripod is unavoidable.

Also found Cannon 5D handles high ISO noise quite well. With noise reduction switch on, it only becomes visibly grainy at 1000 or above.


0.005sec (1/320); f/9; Focal Length:105 mm; ISO Speed:400; Exposure Bias:-1EV;Flash No; Using 20mm extension tube
 

0.005sec (1/320); f/9; Focal Length:105 mm; ISO Speed:400; Exposure Bias:-1EV;Flash No; Using 12, 20 and 36mm extension tube
 

6 avril

色情郁金香

花园里的郁金香开了一大片。忍不住手又去拍了几张。

母亲带回国几棵球茎。每天精心护理,可在南方亚热带气候下连芽都没发就香飞魂
散了。我这次是圣诞节前种的,没怎么打理却纷纷开了。一方土养一方花阿。
后期加工了一下,成了油画效果。颜色艳得有色情嫌疑。

发自Flickr
4 janvier

几个摄影光学术语

Vignetting (暗角)分下面几种:
1) 机械/物理暗角 (重叠滤镜,不正确使用遮光罩)
2)光学暗角
3)  (数码相机特有) 点阵暗角

Lens Flare/Ghost (光环/魅影)正对强光源拍摄导致光线在镜片间弹射造成。

Barrel Distortion(鼓型曲变)- 影相鼓起,向外弯曲(如贴在啤酒桶上一样)发生于镜头广角端

Pincushion Distortion (枕型曲变)- 影相凹下去,向内弯曲(如贴在碗里一样)发生于镜头长焦端

Chromatic Aberration (色散)- 和镜头质量有关。对数码相机来说和CCD的质量也有关。

参考:http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/990/ON-CAMERA-LENS/overview.html
30 décembre

弱光摄影笔记

拍摄

用DSLR 选用 RAW格式 - 画质无损失 后期处理更方便。(JPG格式压缩了文件,又加了一些相机定义的调整配方,不好) 三角架拍摄,按暗处侧重测光。如雾景适当开大1/2到1级。这时如检查片片,你可能会觉得画面偏亮,高光处暴光过度。不用担心,目前关键是捕捉细节。正常暴光的话可能暗处细节就没了。

回家整理片片

各相机的RAW格式都不同,Photoshop CS2 可能可以处理(我用的是CS,要加装插件) 最好还是用随相机的厂家软件处理。我用的是佳能的随机软件。调什么呢?主要是白平衡和暴光,还有就是程序配方。

佳能大概有‘人像’‘风景’‘中性’‘忠实’和‘黑白’几种。我选择了黑白。

然后又有可选滤镜。拍黑白胶片的朋友可能知道各种滤镜的作用。比如深红可以加强对比突出细节。 因为考虑到雾影的效果,我在这个片子里用了黄色。然后转换保存RAW格式到TIFF格式。这时的文件是最大的,有70多兆-画质无损失 是有代价的。

然后用Photoshop打开TIFF文件。等文件加载。如果内存不够大(512Mb或以下),你就先去冲杯咖啡吧。

把画面放到100%,局部一点一点检查。高光处用‘Burnt tool' 5% 暴光的棉球扫暗一点。低光处用‘dodge tool' 5% 暴光的棉球加亮一点。一点一点加,不要企图一下加到20%。

这张片片里,左边火车头驾驶室里是减暗了点的。远处火车照射出的灯柱是加亮了以突出戏剧性效果的。

最后保存成JPG就行啦。这里使用的技巧和普通暗房处理是一模一样的。我在Photoshop数码照片处理上还是菜鸟阿,大家斧正阿。

16 janvier

The pain and joy of waiting game

I counted lab processing is part of the fun of using film compared to digital ones (Digital image vs Slide Film) Now the fun becoming a torture. I sent a process order to www.fujilab.co.uk at the beginning of Jan, yet I am still waiting for it.

Check their web cam a few times (regret I didn’t take a chronicle screen shots). The lab looked like is being dismantled and they promptly shut it down – maybe follow my complaint?

From the email to them:

...

A few days ago got through to the processing lab, they told me there was a backlog and it was in the queue. Factoring the potential length of the queue and the typical 48 hours turn around time, I can see no reason why it is still not done. Checking the web cam is certainly worrying - like the lab is under construction or being dismantled. By the way the web cam snap shoot was last updated at 07/Jan, would that mean it has been disconnected since then?

...

And the webcam still as of writing

And what it look like now?

Yeah, great got to sit tight…

19/01/20006 Finally I got the slides back...

11 décembre

Photographer: what are you looking at?

Camera legend O'Neill lashes dismal digital - Sunday Times: "The problem with it is that the picture taker keeps on looking at what he's just done rather than look at the subject."
 
This is a very insightful comment. I think O’Neil is referring to checking the photo you just took so you can re-take if it is not satisfying. You never need to think to take a picture.
O’Neill points on that because the cost of taking a digital photo is so negligible, people lost their skill or patient on observation and putting ‘thoughts’ on shooting a picture, which is the essence of making a good photo.
 
I change it a little bit: the time you spent on ‘touching up’ a photo using picture editing software.

Here is my proposed formula on measuring how good a photographer is:
C: time spent on initial shooting
U: time spent on checking-retaking a photo;
N: number of retakes of the same subject.
T: time spent on after-shoot process; count photo editing using software, or extra time required for darkroom process (if it is taken in film) 
W = C+N!*U*T
With two similar quality of pictures, the smaller W is, the better photographer you are.
 
Example 1:
Taking a digital photo; C = 3 seconds (you didn’t bother to wait to take)
Checking a photo 5 seconds and retake 3 seconds; U = 8 seconds
Retake the same subject twice N = 2
After-shoot processing: software editing  T = 30 minutes = 1800 seconds
W =  3+2!*8*1800  =  28803
 
Example 2:
Taking a film photo; C = 1800 seconds, (setup, waiting for the right moment 30 minutes)
Retake 1 seconds; U = 1 seconds
Retake the same subject twice N = 2
After-shoot darkroom processing, additional time spent:  T = 1 minute = 60 seconds
W = 1800 + 2!*1*60  = 1920
 
You are 15 times better as a soulful film photographer.
 
[Note] While working on this formula, I realize the value of a digital camera as in travel or time pressing, fast changing events. You just don’t have the time to think and observe.
11 septembre

Digital image vs Slide Film Print

Dixons has recently stopping selling film camera. A shocking news but probably shouldn't be too surprise. They stopped selling VHS recorder a few months before. High street chain retailers are chasing profit than anything else.


The fact is digital camera is cheap and convenient to use. At tourist hot spots, you will find everyone is waving a palm size digital camera with a huge LCE display at the back. Point and shot, check it. uhmmm... don't like it, delete and re-take. You don't need to think to take, you don't need to observe the transit moment, just press the button. A 'nice' picture comes easy.


Compares to this, a film camera is much expensive to use. Got to confess than I give up colour negative for many years. I only do black & white negative and colour slide. And only these two medium give me the reason to not to use digital one. A 36 exp black & white costs around 4 pounds, develop the film costs time and chemical, say 5 pounds. Each print takes about 30 minutes to do, with test strips and experiment prints, probably two hours. A 36 exp slides costs 8-10 pounds for the film and processing. Print is an extra, at 20 pounds plus for 10X8 each. So you got to be more assertive when pressing the button.


Being cheap to use is an advantage for digital camera. However, it kills the fun and aesthetic bit of photography as a hobby. You know the anxious waiting time; burn and cover up under the enlarger; trying out different timing; seeing the grey scale emerges from the pan under the red light. And don't forget the pride of showing off the slides by project them to the wall in the darkness while telling story to your friends.


There are lots of debate on print quality as well. A comparing method is to compare digital image with scanned photo  on screen. I think it is not fair to poor slides that it has to suffer an extra scan process. It then losses some fidelity. Another method is to print the digital image and compares the print qualities to slide prints. But someone argue that it is not fair to digital because printer quality is dominated.


Not really into these debates. I like the vivid colour and depth of slide, and rich grey scale of B&W. There is just no matched-up in the digital world. Even the best one I have seemed still look like flat, dull. But if for photo journal or on-spot shoot/online publishing photo blogging (I am planning one at the moment), I will go for digital. Just the prints probably won't have a chance to be hanged in the lounge. If I could make an analogy on comparing digital image to film image, it just like comparing video recording to cinema movie quality. Think about how they are made - not really a surprise isn't it?

The hobby is back

I finally sit myself down at this dismayed Sunday afternoon for some serious hobby that been listed in the 'TODO-now list' for more than three years.

You see, I like photography and travel. These two are the prefer compliment to each other. I have even setup a darkroom for enlarge and print in the garage but never really use it since it was built. I still took photos in slides and black and white film, but they normally ended-up in the shelf for my own pleasure.

Friends ask me, 'Why don't you share your photos online?' Believe me I have tried since three years ago. But all ended up nowhere as I always wanted to built a site from ground zero.

Still not very comfortable on sharing photos using third party (e.g. msn) service. I know, everyone does so nowadays. It is just me.

Based on the velocity, I find that an quality afternoon (i.e. no one is yarning or messing around in the house) could afford me to tidy up two photos with minimum modifications.

If I could keep it like this, all photo frames we bought two years ago should be very quickly put into use once I get them print. :-)