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 :P

- 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!

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.  

Thanks,

Babar-Photography 

Facebook , Twitter , Flickr , 500px , YouPic