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.


Monday, February 12, 2018

The Future of Silicon Wafer technology in Digital Photography

Silicon wafer technology is reached to its maximum limit now. There is nothing new to offer by all these camera companies when it comes to sensor technology to be honest. Number of Mega pixels are pretty much limit on both APS-C and Full Frame now. You cannot cramp more than 24MP in APS-C sensor size which ultimately gives you around 54-56MP over the Full frame if you keep the same pixel density. Why i am saying this? Reason is, if you have more then 24MP on APS-C size sensor, the Dynamic Range and SNR performance of that digital sensor degrades exponentially. So 24MP is the optimum threshold and all camera companies are making DSLR around it. Only Samsung have one model which got 30MP i guess on APS-C size sensor and its DR and ISO performance is way worse.

Now i have used a word "same pixel density". What it means that both APS-C and Full Frame having same number of pixel per square mm. Best examples are Nikon D7000 (16MP) which gave us D800 (36MP). Then we witnessed 7D MK II (20.2MP) which ultimately leads to Canon 5DS/5DSR. And then in last the world witnessed the Nikon D500 which leads to Nikon D850. All these cameras used the same pixel pitch which means the size of the pixel on APS-C and Full Frame remains the same. So what exactly makes any Full Frame camera works better then APS-C if both are having the same pixel pitch? We will discuss that in some future blogs. Lets stick to the sensor technology future right now.

Here is the funny part. The more pixels you going to push into the sensor (regardless its APS-C or Full Frame), the more DR you are going to lose. It means pixel are becoming smaller and smaller day by day and their ability of light capturing the light is becoming limited. The more pixel is going to be smaller, the quicker it will fill up with light which ultimately going to reduce the ability of recovering shadows or reducing highlights in post processing. The only salvation is nothing but "SNR firmware updates" which going to make the performance difference and help these companies to offer the new model with improved ISO performance based on keeping the same 24MP count. I guess I have unlimited times mentioned in many posts about this fact ISO has nothing to do with exposure because it is APPLIED Gain which applies on the "capturED" image after the sensor. All these camera manufacturing companies releasing different models based on the different SNR software. Best example is Nikon D750 which used the old Nikon D610 sensor but due to its strong SNR firmware its performance is still unparalleled in the category D750 stands in.

Now on horizon, there are 2-3 new tech coming. As now we have learned that you cannot have more than 24MP in APS-C sensor size, so what is selling point of future DSLR? Increased number of pixels or improved ISO perhaps !!! The only way to increase the pixel density is by changing the architecture of the sensor which is ...... BSI sensor. (Please google about BSI sensor if you don't know what it is). In brief, the traditional digital sensor pixel wiring from the top of the photosite which blocks the light by a huge amount. In BSI (Back Side Illumination) the wiring of the photosite is underneath the sensor which make photo receptor to capture more light then before.

By wiring the photosite (AKA pixel) from the back of the sensor we are actually having around roughly 30% more light coming into the same tight pixel which means we will be having the better native gain. Now in order to take advantage of having this extra gain, what these companies are working on right now is, they are cramping more pixel into the same tight APS-C size sensor and then using the same SNR technique which they are using on other camera models, they are maintaining the same (probably better) ISO performance on the APS-C size sensor by having MORE then 24MP. This is how companies are using SNR as an extra leg of the exposure triangle and playing with the sensor technology and making money at the same time.

Soon we will be having around 28-30MP max keeping the same Dynamic Range & ISO performance variance on Fujilfilm X-T3 just like X-T2, but this time, mega pixels will be more then X-T2. Just like X-T1 when it had 16MP but they released the X-T2 with more mega pixels and better SNR software which makes X-T2 a legendary camera status. Now history is going to repeat itself for X-T3 and again we will be having more mega pixel on X-T3 (thanks to BSI sensor) and with improved SNR. Other camera companies will be doing the same.

So BSI sensor is the next big thing which is already available now and giving these camera manufacturing companies to WORK AROUND their way (as silicon wafer technology is already hitting the ceiling/threshold of 24MP) by using BSI sensor. There are around 50 new ways of making any sensor efficiently using different architecture and sensor manufacture techniques and BSI sensor is just one example.

In future, you will be seeing curved sensor (which required total new lenses line up) and "Adaptive resistance" sensor which will be making HDR image right from the camera, and i am not talking about that HDR option in your DSLR which only works on JPG. in Adaptive resistance, it will be applying directly on RAW.

Time to wrap up this small blog showing the limitation and workaround of any digital sensor coming in modern day DSLR. Hope you like it.

Happy Learning guys.


Saturday, January 13, 2018

Interesting finding about new Nikon 180-400mm f/4E FL lens.

Today I read about the new Nikon 180-400mm f/4 E FL lens who’s price is in 5 figures ($12,999). And then I went through the specs and all fancy features which that lens is offering. But while I was reading the description of the lens, I came across a very interesting fact which I like to share.

The lens is 180-400mm f/4 constant aperture. There is also 1.4x Teleconverter built in. Now this leads to some interesting fact, 

The effective focal length without 1.4x TC
A- On Full Frame: 180-400mm f/4
B- On Crop Sensor: 270-600mm f/4

The effective focal length with 1.4x TC
C- On Full Frame: 252-560mm f/5.6
D- On Crop Sensor: 378-850mm f/5.6

Now this looks like a typical boring calculation. But Point-C caught my attention. This resulting focal length and aperture is almost the same like Nikon 200-500mm f/5.6E lens which is 1/10 price of this expensive lens. So quickly some question POP UP in my mind, 

- Why this new lens is 10x the price of the cheap 200-500mm f/5.6E lens?
- Will it there will be performance difference between the cheap 200-500mm f/5.6 E lens vs ultra expensive 180-400mm f/4E FL lens?

The answer of the first question is simple. I believe Nikon is now virtually making 2 type of products. One is for total Pro which is expectedly expensive which comes with full blown out performance features. And then there is “lite” version of the same heavy product but with some trade off of the features but at affordable price. Best examples are D7500 which is a LITE version camera of D500. Cameras like D750 and D610 which carry the same sensor but D610 is little inferior when it comes to AF points and ISO performance unlike mighty D750. 

For second question answer, Yes there will be significantly performance difference between the 2 lenses. The 200-500/5.6E will be not as fast as this Pro 180-400/4 (with 1.4x TC) when it comes to fast and bang on AF. There are not focus recall buttons of 200-500/5.6E lens. Focus recall memory button is a huge deal for the wildlife, specially bird photographers which is present on 180-400/4E FL lens but not on 200-500/5.6E . People also needs to learn that AF is not only depends on the lens but also on the camera body you uses. AF performance is the combination of both camera and lenses you used on it. Then comes the VR function. This is the point where I personally believe both lens will neck to neck. I have used 200-500/5.6E lens and its VR function is insanely damn good. I have shot at 1/20 second @500mm handheld and the image was tek-sharp. I am sure that 10x expensive 180-400/4E FL lens is no less then 200-500/5.6E when it comes to VR. As far as optics goes, 200-500/5.6E already proven itself. Now lets see how the big brother will be doing in the real life scenario.

Now last thing and most important thing, which lens shall I buy as both are serving nearly identical focal length and aperture (using 1.4x TC)? Shall I go with 200-500/5.6E Lite version? Or go full-on Pro version of 180-400mm f/4E FL lens? Answer is its up to you. Its totally depends on how deep your pockets or how much funded you are. But most importantly, does your work really ask for the Pro 180-400mm f/4E FL lens? If yes then why not. For people like me I am more then happy with 200-500mm f/5.6E lens as it is full filling all my needs. I highly recommend that lens. But yes at the same time, stand alone 180-400mm f/4E FL lens itself give you 1.4x TC flexibility which is not present in 200-500mm f/5.6E. Choice is yours.  

Happy Learning.... 


Saturday, September 16, 2017

Photography Themes and its effectiveness

Today it suddenly hit me when I was posting on some famous photography forum an image based on the "Theme" .... following points quickly came into my mind. 

- Are these themes are really helping us in study photography .... and I mean the photography?

- Or are we just trying to copy paste the example that was shared with the theme for illustration?
- Even if it helps people for learning photography (assuming in an ideal world) ...... so it means we are like going to the school study the same set of books which our ancestors went through and ultimately we all ended up like them ..... isn't it !! ..... So where is my identity as a unique photographer?  Honestly, posting images for themes like you are trying to get A+ in all subject and you know that its difficult (though not impossible) because photography is all about how our mind is wired to see things. 

- Let say if it is not helping me to learn something unique ..... then it just another marketing gimmick to sell your PAGE MANJAN where people gather ..... do confrontation (my fav. thing) ..... do push and pull legs (you know what I mean by that) ...... share our images and get the oxygen of "LIKES" ..... so where learning in this? 

- Let's assume in ideal condition these themes really helping many people. But what happens after themes end? we go home and sleep .... goodbye learning. How many people who said they like the themes to work with are literally applying those themes for "THEIR" Photography? You know the answer of that. ..... isn't it 

- I have YET to see any theme which teaches about how to study light. it is more about forcing people to follow the rules which always meant to be broken. Other 1 or 2 guys ... I have not seen a single person among thousands who really knows about light and how to play with it. And those people work is worth watching. And they usually don't do photography for themes. They do it for themselves. So the biggest question is ...... A true photographer should be a born photographer who completely free from the filth of gears and stuff and just focuses on the pure soul of photography which is light. And no theme can teach you light that's for sure ... You are born with the codec in your mind to decode the light or you just can't no matter how expensive gear you have. 

- By posting themes, we are making machines of photographers with pre-defined codes in their head. They are afraid of taking chances and following the market trend Their coded mind is so closed loop that they can fight back to death to defend those codes and among them the highest RATED code is ..... JUST DO WHATS GOING ON IN THE MARKET IF YOU WANT TO MAKE MONEY. 
All I can in the end ...... it doesn't matter if these photography forum/pages are or us as an individual ..... WE ALL ARE RESPONSIBLE MAKING DUMB@$$ MACHINES OF PHOTOGRAPHERS ROBOTS IN OUR COUNTRY WHO DOESN'T KNOW AND DONT WANT TO KNOW WHAT PHOTOGRAPHY SOUL IS ALL ABOUT, BECAUSE THEY DONT HAVE TIME FROM ........ you know the rest. 

The End!

Monday, May 22, 2017

Why Sensor size has nothing to do with the Depth of field?

Yesterday i posted a fact on FB that "Sensor size has nothing to do with the DoF". And then i was waiting for the replies becuase i knew that some one will reply. But surprisingly one of very dear Photographer who is a Doctor in States and i have so much respect for this gentlman replied which i was expecting. And his reply was spot-on right. He said what i said is not correct and Sensor size does effect the DoF if we shooting same subject from same distance.

What he said was right and 99% of photographers, I am sure you too agree and endorse what he said. In general understanding the “Depth of Field” works like this which he mentioned ……. BUT only if you try to achieve the similar “angle of view” using different sensor size.

Allow me to go deep and unfold the mystery which not many people know. The first thing that we need to understand that different sensor sizes have different field of view at a given (fix) focal length and distance. 5x4 got bigger field of view, then medium format got smaller angle of view then 5x4, similar goes for full frame, then APS-C & least angle of view is for Micro4/3.

I am going to use FF & APS-C sensor sizes to explain why Sensor size has NOTHING TO DO with the Depth of Field (DOF). But before we go any further, another thing that we need to understand that any lens …… say 16mm focal of a crop body will be 16mm regardless it is used on FF or APS-C or even Medium Format. It always remains the 16mm. But as we understood earlier that angle of view for every sensor is different so to achieve the “similar angle of view” from a 16mm lens at a “Given/fix” distance it wont be possible. Why? Because 16mm is 16mm ….. and always remain 16mm. Its physical focal length never changes no matter you use it on FF or APS-C so the angle of view “from that lens” will remain the same. Its like you small tap/nozzle in the garden to sprinkle water. No matter how much pressure/volume of water is behind, the amount of water coming out from the nozzle will be totally depends on how much tap/nozzle you opened. Same applies here. The DoF will remain the same because we are assuming that we are shooting using a fix focal length, fix aperture and from a fix distance no matter what type of sensor is beneath it.  So what will be the output “angle of view” if you use 16mm crop lens on the follow digital sensor?

APS-C --> 16mm --> 16mm angle of view

FF --> 16mm --> 16mm angle of view

Medium Format --> 16mm --> 16mm angle of view

The angle of view will remain the same no matter what sensor size you used the lens on. Now if ever used the crop body lens on a full frame body or full frame lens on a Medium format body (using special adaptor) then you will be noticing that it creates heavy vignette. Why? Because optically the 16mm that was used above for an example was design for crop sensor which is 24mm x 16mm in size. So the circle of project of light from that 16mm lens was meant for 24mm x 16mm crop sensor. Now if you use the same lens on FF which is 36mm x 24mm sensor it means there are extra area on the sensor which is not covering by APS-C lens. That’s where that “Extra Angle of View” kicks in of the larger sensor format. Now we need to redesign the lens which covers the extra area of the 36mm x 24mm FF sensor. Now to cover the whole FF sensor & to achieve the similar angle of project of 16mm crop, optically you have to design a lens of 24mm and only by then you will be having similar Angle of View between FF & APS-C. So what focal length of FF & Medium format we need to get equal angle of view of 16mm APS-C?

APS-C --> 16mm --> 16mm angle of view

FF --> 24mm --> 16mm equivalent angle of view

Medium Format --> 30.5mm --> 16mm equivalent angle of view

Now many of you will wonder from where that 30.5mm focal length comes for Medium Format comes? It came just like crop factor of 1.5 came ☺ . Now divide the focal length of the lens by the following factors and you will get the equivalent angle of view.

APS-C = 1.5
FF = 1
Medium Format = 0.79

BTW besides the lens multiplication factors, these lens manufacturing companies when they redesign the lenses for different digital formats, they redesign the Aperture opening accordingly which is based on focal length “f/1.4” that “f” is focal length. So ones the aperture value is changes, it also effects the DoF. In general there is a “one stop” value difference of DoF value between the different sensor format. For example

M4/3 f/1.2 = APS-C f/2 = FF f/2.8 = Medium Format f/4  

But these are just practically assessed values and 95% of lenses are made on this.

As you have seen that focal length is changes to achieve the similar “angle of view” which ultimately changes the focal length of the lens, which also changes the Apeture opening of the lens, which ultimately “indirectly” effects the DoF. So what I stated above is correct that sensor sizes has nothing to do with the DoF ..... directly. 
So I hope after reading all this lengthy details, it will be cleared now.  


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