Tuesday, January 15, 2019

Sensor Size doesn't effect the Depth of Field

Ok, VUEmbers .... here is the thing. I am big advocate of doing things with own hands and to verify stuff before I start believing on things over the internet. I often heard and read from the internet that larger the sensor, shallower the depth of field. So i thoughts lets test this and see what exactly happening in the world of photography by having 3 different digital formats. Here is the breakdown with real-world examples of the following 3 digital Format,

From Left to Right,

Full Frame: Nikon D700 + 24mm f/1.4G
APS-C: Fujifilm X-T20 + 16mm f/1.4
Micro 4/3: Panasonic GH5s + 12mm f/1.4

All these 3 digital formats cameras are covered by their respect focal length lenses which covers the same angle of view (84 degrees) which are 24mm (for full frame), 16mm (for APS-C) & 12mm (for Micro 4/3). All these 3 lenses are having a maximum aperture of f/1.4 in common, which means they pass the same amount of light regardless of being the different focal lengths in reality. Therefore, the exposure on all 3 formats is the same except that Nikon highlights are little more than usual (my mistake). Settings on all 3 formats cameras were as follows,

ISO:200 | f/1.4 | 1/100

Now this quick test I did is not for the quality of the Bokeh or how lenses/sensors are rendering the image. It's more about why the depth of field (Area in focus) is different in all 3 images regardless of being three f/1.4 lenses in common.

Now some of you already know the answer in detail and most of you will say well it's because of the bigger sensor size. Well in reality (and as the caption of this blog says) sensor size has nothing to do (directly) with the depth of field. As three different formats capturing 3 different "area or angle of view" in the real world, therefore, in order to obtain the "EQUAL" angle of view we have to design the lenses with different focal length which ultimately leads us to the famous term of "crop factor". Now let me clear at this point right away that this crop factor has no connection what so ever with the depth of field. It is just a reference to understand and bringing down different digital formats at one level. It's just like if someone ask you how many centimeters in 1 inch and you quickly say it's 2.54 centimeters or 25.4 millimeters and all will give you equal length in physical world.

1 inch = 2.54 centimeters = 25.4 millimeters

Same goes for the angle of view. All below 3 focal lengths will be giving me the same angle of view.

24mm (FF) = 16mm (APS-C) = 12mm (Micro 4/3)

Are you guys with me so far? I hope so. Now the big question is why depth of field is changes by changing the format regardless of having f/1.4 lens. The answer is FOCAL LENGTH. As we know that depth of field is changes by the following 3 parameters.

- Aperture (All were f/1.4 in this case)
- Distance of shooting (were the same in all 3 cases)
- Focal length (longer focal length produces more shallower Depth of Field)

So, as you can see, when you change the format and try to achieve the same angle of view by keeping aperture constant, the only parameter which is makes the bigger impact practically speaking is the focal length. This is why when you move to medium or large format cameras and try to achieve the same angle of view with constant aperture, you will end up using longer focal length lenses on the medium/large format cameras causing massive shallow depth of field which make these format stands out. You can check sample image of the medium format using this link where image was taken by Fujifilm GFX 50R with 45mm f/28 lens (equivalent to 35mm f/2 for full frame, or 23mm f/1.4 on APS-C).

Now let me share with you the 3 examples next which I took using the same aperture, shutter speed and ISO value also from the same distance.

 Full Frame


Micro 4/3

I hope you will find information useful and it will help you in making great images. If you still kind a confuse and not able to get what i explained, then i suggest to check out this video from fstopper.coom people who explained it well then me i guess. Please do visit our Facebook group VUE for more technical stuff related to Photography.

Happy Clicking Guys.

Babar Swaleheen

Saturday, December 8, 2018

Heavy vs Light weight Tripod/Monopod

When it comes to traveling, it is always advised by millions of photographers that carry light weight gears. This is where mirrorless cameras a becoming handy and i agree with that. As i am getting older and having severe knee pain, carrying heavy DSLR is not my preferred choice. I prefer to take shot using my Fujifilm X-T20 and use old legacy Nikon lenses on it using a dumb adapter with Aperture control so even i can use my Nikon G-Type lenses on them. D-Type lenses already have aperture control on the lens.  

Now coming back of being light weight travel photographer, i often see people referring carry Carbon fiber Tripod/Monopod. This is a point where i have some concerns which i wanna share via this blog. 

Travel photographer are mostly travel to capture landscape shots among which heavy amount of images are long exposure shots. This is a point where i prefer to have heavy tripod, not light weight carbon fiber stuff. Let me explain why. 

As now Mega Pixel war is sky rocketing, the term "Micro Blur" is something that everyone who got more than 30~36MP camera must know about. Micro blur is basically a motion blur introduced into your image due to very tiny shake happens when you press shutter release by the time your exposure ends. Majority of the time it is introduced/triggered by pressing the shutter release itself. Images which are shot around 1/250 shutter speed or less are heavily subjected to have Micro Blur in it if proper pre-caution are not taken care before taking the image with these massive mega pixels cameras. Even slightest of the wind blow can shake your tripod if you are shooting with tripod legs fully extended and if its light weight. Even a strong current of sea wave can make your tripod shake while you are taking some long exposures shot with some foreground element in the frame. With camera like Nikon D850 or Sony A7R3 or Canon 5DS/5DSR will make these micro blur prominent like any thing when you view them at 100%.

It is a simple physics that any heavy object is hard to move around. This is why i prefer to have old heavy DSLR with heavy lenses and heavy tripod so i don't have to worry about any kind of shake at all. Now choosing mirrorless over DSLR is totally user dependent and based on the latest "fashion" (thats what i called). But choosing heavy tripod is something that you must consider it regardless you are heavy DSLR shooter or light weight mirrorless. By choosing a heavy tripod you are basically creating extra layer of protection for yourself if you are shooting long exposure and you are having higher megapixels cameras. 

Now here is another thing i like to share which is interesting. I have explained above in detail that your tripod must be heavy. But when it comes to monopod, i suggest otherwise. When it comes to Monopod, your preferred choice must be a light weight carbon fiber monopod. Now again why light weight carbon fiber monopod? Before i answer this question i have another question for my blog readers. Why we use Monopod? The basic and most common answer is TO EASE our hands and shoulders from the heavy gears that we are carrying around. Monopod is basically use for longer focal length lenses like 400/500/600mm focal length primes or Zooms like 200-500/5.6, 120-300/2.8 or 150-600mm lenses. Maneuverability is something which make us use Monopod over Tripod. So the lighter the monopod is going to be, the better maneuverability is going to be for us when we shoot sports/action/wildlife. 

So based on my brief experience, i suggest you all that heavier tripod and lighter monopod will help you in getting better and sharper images regardless what ever gear you are using. 

Happy Clicking Guys !

Babar Swaleheen
Flickr 500px Instagram Youpic

Wednesday, December 5, 2018

My first image using medium format  Fujifilm GFX 50R

Sunday, November 18, 2018

What is the advantages and disadvantages of using medium or small RAW files

Today I ready a question about will different RAW format (small or medium) going to effect the image quality? I believe question is totally valid. So lets get dive into the techie details.

If anyone knows how sensor, SNR firmware and how different form of sampling works when you do file compression then these full size RAW, mRAW & sRAW practically doesn't matter at all when it comes to image quality. Allow me to explain how.

Image quality depends on per pixel, NOT the total number of final pixels you are getting, and how you extract data from the sensor using SNR firmware. When you press shutter release, camera sensor exposes ALL pixels and it goes into the buFree. From there you filter out the data PER PIXEL which came from the sensor and then start packing the bits of each pixel into medium and small BOXES (medium or small RAW) using compression algorithm. So in short, what you getting from the full sensor is what you going to pack ultimately into medium and small packets .... Right!

And that perception that full raw image looks more sharper than medium and small RAW, is depends on many factors like your display resolution, lens fadility, software glitches which is suppressing the full RAW information into medium and small RAW which is causing loosing quality of the image as we are downsampling it. Many people don’t know that when you downsample any information, YOU CANNOT CREATE INFORMATION WHICH IS NOT THEIR AT THE FIRST PLACE WHICH WAS DISCARDED AT TIME OF COMPRESSION and making medium/small raw file. Therefore if you see that your images are not as sharp and full with quality the way it is in full size raw then now you should know why.

So in short, who ever using D850 with small or medium raw file size is basically not utilizing the full potential of it. If you really feel like you need 25 or 11 MP from D850 then better buy a used D750 or D700 to get the similar 24 or 12MP in more efficient way at very cheap price in compared to expensive D850. In this way you will be having at least back of D850. Keep your D850 for exclusive shots and use D750/700 for regular stuff. Note that processing D850 files itself makes you to upgrade your computing resources. So yes having D850 is basically a blessing and curse at the same time depending how you take it and how deep your pockets are.

Babar Swaleheen
Flickr 500px Instagram Youpic

Saturday, April 21, 2018

Using a medium format lens on regular DSLR

10 days ago, while i was searching for some unique manual focus lens, out of no where i came across one dumb/passive adapter using which i can use specific set of medium format lenses over my Nikon DSLR. That adapter basically enables Pentax 6x7 medium format mount to coupled with Nikon F-Mount. You can find that mount using this link. 

So why using this adapter? what so special about Pentax lenses. Cut story short, Pentax had a rich history in making some really nice medium format lenses which produces some really highly saturated colors and some yummy contrast keeping the sharpness to the max which is not a common thing even in modern day lens design. So using that adapter, now you can buy cheap Pentax 6x7 medium format lenses and use it. Of course they will be manual focus only due to the passive adapter. So if you are manual focus user, then this blog is a dessert for you.

When i had the adapter with me, for experimentation purpose, i  ordered 135mm f/4 from Asahi Pentax SMC Takumar Macro lens just for testing purpose. Why macro? because i dont have any macro lens with me right now.

Ones i received the lens. i used that passive adapter and couple it with my trust worthy Nikon D700 and results were really good. Let me share a Youtube video using this link and sample shots below. You can clearly see the difference in performance between old Nikon legendary lenses vs some old Pentax medium format lens.

Below are Sample Shots from Pentax SMC Takumar 135mm f/4 Macro. Note that for comparison, i had 2 additional lenses (Nikon 135mm f/2 AI-S & 135mm f/2.8 AI-S lenses). Typically speaking, f/4 on medium format is roughly equal to f/2.8 over Full Frame. Therefore, Nikon 135mm f/2.8 Ai-S is the nearest choice to compare with Pentax Takumar 135mm f/4 medium format lens.

Note that these below images are straight out of the camera with no editing what so ever.  The shot was taken by both lenses using the same distance and same EXIF data. Left shot is from 135mm f/2.8 AI-S. Right shot is from Pentax SMC Takumar 135mm f/4. You can clearly see how much rich color and contrast Pentax lens is producing. 

Some more shot. Left is 105mm/2.8 AI-S. Right is from Pentax SMC Takumar 135mm f/4.  

Bottom Line:

- Bokeh from 135/2.8 AI-S from Nikon is the same like 135mm f/4 from Pentax Takumar. 

- Pentax SMC Takumar producing some really nice rich color & high contrast images right from the camera. 

- The Bokeh from Pentax SMC Takumar 135mm f/4 is some how detailed.

Thanks for stopping by. See you soon. Happy learning guys. 

Babar Swaleheen
Flickr 500px Youpic

Sunday, April 8, 2018

A brief note and explanation about lens equivalency

Have you ever wonder how come lens equivalency works across different digital formats? Today I did a small illustration using the coffee mixing sticks. 

In this illustration, I have tried to show this idea that if you want to achieve the same angle of view across full frame and crop sensor then how and why you need different focal length. Why 50mm on full frame gives an equivalent angle of view of 75mm on the crop sensor. The answer is, to cover the large area of the sensor (which will be FF in this case) you need a bigger circle of projection which means you ultimately have to design lenses of a smaller focal length (50mm in this case) which ultimately covers the full frame. 

In case of a crop sensor, you have less area to cover which means the small angle of projection you need to cover the entire sensor which ultimately achieves by designing the longer focal length lenses. Longer focal length produces a small angle of projection. 

Hope this simple illustration will clear this confusion that why 50mm on Full Frame is equivalent to 75mm on a crop sensor. Also, note that through this illustration, physically focal length has nothing to go with the sensor size. You can switch the focal length and results from the 75mm will be 75mm and 50mm will act as a 50mm. If you switch 50mm on a crop sensor, it will remain 50mm and will give you the same depth of field of 50mm because physically the focal length does not change so this non-sense idea which circulating around the photography world that if you use Full Frame lenses on a Crop sensor camera bodies "multiplies" your focal length and gives you extra reach .... is total NON-SENSE.

Happy learning guys. 

Babar Swaleheen

Saturday, March 3, 2018

There is no such thing as a Lens Equivalency & there is one more thing .....

I was not feeling good to go out for shooting so thoughts let not waste time and do some experiments at home hands-on rather than trying to convince people by breaking the keyboard.

I have told endlessly at on various photography forum that focal length of any lens is a number and it has NOTHING TO DO with the sensor size or thing call "Equivalent" focal length. NO, IT'S NOT EXISTS. 50mm is a 50mm across all format of sensors. I did a little experiment at home and I used 2 lenses on Full Frame Nikon D850.

A- Nikon 35mm f/1.8G DX (Crop Sensor Lens at the left-hand side)

B- Nikon 35mm f/2D (Full Frame Lens on the Right-hand Side).

To some people, it will be a shocker to see that Left-hand side DX lens almost not produced any sort of Vignette at all on the full frame body. There is very very small sort of vignette which was expected because of the small circle of projection by the DX lens on the FX body but the magnification of the 35mm DX lens at the left-hand side is the same just like a Full Frame 35mm f/2D. This proves nothing but a simple fact that there is such thing call lens equivalency. A 35mm focal length is a 35mm focal length across both formats. I said multiple times in past at various photography forums that LENS HAS NO IDEA WHAT SENSOR BENEATH IT. THEY PASS THE SAME AMOUNT OF LIGHT TO THE SENSOR REGARDLESS.

And there is ONE MORE THING .....

Check the second image screenshot down that I took at 100% view and look very very closely. Why the right-hand side image looks more 3D in compared to the left-hand one? I guess we already discussed a lot lately about the 3D characteristic of some old lenses which not many people know about it .... And here is the proof of it. Many old manual focus lenses produced 3D projection images on 2D plane sensor with rich color, sharpness and high contrast. I took the image where ISO, Aperture & S.S. was the same including the distance of the camera from the subject including did NO POST EDITING AT ALL and YET Right-hand image is more saturated, more contrasty and it is literally JUMPING out from the screen, unlike the left-hand side. Click on the image and look closely.

Next experiment will be done about the performance of the APS-C vs Full Frame with hands-on evidence showing that now it doens't matter what format of DSLR you have, they all are performing the same. The performance gap of the APS-C vs Full Frame is almost gone now. Wait for the next blog guys.

Happy Learning.