Go Back   Team-BHP > Around the Corner > Shifting gears > Gadgets, Computers & Software


Reply
 
Thread Tools Search this Thread
Old 3rd November 2009, 13:58   #1876
BHPian
 
SPARKled's Avatar
 
Join Date: Aug 2009
Location: Navi Mumbai
Posts: 925
Thanked: 294 Times
Default

Quote:
Originally Posted by it_inspector View Post
Well we are comparing Lens Apeture and since its a FIXED size, it doesn`t change with lens type or reach.

We are not comparing the system or sensor. We are comparing the APETURE.

Nothing else effects APETURE in a lens that itself. Please read above to see what an APETURE looks like. APETURE is a PHYSICAL thing-maximum SIZE of the hole in the lens to let the light pass through which doesn`t gets affected by anything else.

Seriously is it that hard of a topic to understand APETURE and F-no. ??
But an F2 opening of the aperture of a P&S will be way smaller than an equivalent focal length F2 opening of a SLR lens. I have a P&S which has a 2.8 - 4.0 lens and the 2.8 of the P&S is no where close to the opening of an el cheapo 18-55 aperture at 5.6. So comparing F values just as printed values is irrelevant. So a F2 of a P&S will not be equivalent to a F2 of a SLR lens at the same focal length. If this was not the case then how do you explain the the lens of superzoom P&S of say 500mm zoom fits a body of a size of just larger than a palm of a human hand, while the 500mm f4 behemoth of a SLR is a huge bazooka.


Quote:
Originally Posted by it_inspector View Post
Actually you can do a HDR with a single image. Just goto Photoshop and save the original file with +1ev and -1ev and then import all three images into your choice of HDR software and go nuts with it.
Good point. I will try this out.

Quote:
Originally Posted by it_inspector View Post
Actually Nikon 50mm f1.8 is better built since majority of it is cross-sectioned ABS plastic and whole designed is based on older lenses with focusing done via rotating the lens pancake assembly in a barrel and all of the elements are sealed inside a pancake system including APETURE. Since this system allows more surface area to spread the force/weight, its more likely to survive a hit compares to AFS/EFS/HSM lenses where focusing elements are pretty much floating. Specially the new lenses with floating VR/IS/OS elements.
I still feel thats one hell of a lucky 50 1.8 to have survived that and no amount of ABS plastic and the works could have saved it from a direct impact of that magnitude.

Last edited by SPARKled : 3rd November 2009 at 14:11.
SPARKled is offline   Reply With Quote
Old 3rd November 2009, 14:49   #1877
BHPian
 
Join Date: Oct 2009
Location: Bangalore
Posts: 507
Thanked: 57 Times
Default Re: Canon 1000D

Quote:
Originally Posted by rkbharat View Post

How is Canon 1000D, it will cost me around 28K with 18-55mm IS Lens. Should I look for such options or wait to buy a better body.

This will be my first DSLR

Ive been using Canon 1000D since 6 months (Yeah its my 1st DSLR) and i'm prett much impressed with the pictures.
Many of 1st time DSLR buyer have a mentality that buying a Costly cameras will make them a good photographer or will yield a better picture. I dont think it really happens though ive never used a top end cameras (Still an amateur ).
My theory goes like this -spend reasonable amount of money on the Camera, spend on lenses according to the necessity.

Ive been using Sigma 70-300 with Canon 1000D and im pretty much impressed with the image quality and the cost too. (cannot upload the picture as im still a newbie)

Nikon D90 costs close to 80K in BLR with 18-55 lens (which has live view). Compare it with Canon 1000D which comes for 26K with 18-55 lens. Upgrade the lens to sigma 70-300 (Which I did) costing 14K more. All inc - not more than 40K.
Once you are on that level that I'm done with entry level DSLR then put it on sale on Ebay and buy an EXPENSIVE camera.
No office meant.

Last edited by Jaggu : 3rd November 2009 at 14:53. Reason: Removing [Font] tags, avoid using external font editors, also preview before submitting. thanks
livyodream is offline   Reply With Quote
Old 3rd November 2009, 14:57   #1878
BHPian
 
Join Date: Jan 2009
Location: NO ID(e)A
Posts: 60
Thanked: 7 Times
Default

Hi:

Getting a bit confused here. Is aperture is physical dimension defined as the absolute size of opening in the lens, or is it size of the opening defined as a ratio of the focal length of the lens (i.e. f/1.8 or f/2.8 etc.). AFAIK its the latter. I think that it is a fixed ratio and not a fixed size

Continuing with this, will f/2 in a Pana lx3 be different than a f/2 in an dSLR camera (since this determines the amount of light that falls on the sensor). In other words, if we shoot the same scene together with both the lx3 and, say d90, at f/2 and same focal length (or rather equivalent focal length) setting in aperture priority mode, will the shutter speed be different in the two (at least theoritically). If it is, then does it mean f/2 is different from one camera to another??

Kindly shed some gyan.
chaudhrysan is offline   Reply With Quote
Old 3rd November 2009, 14:59   #1879
BHPian
 
Join Date: Mar 2008
Location: Melbourne
Posts: 27
Thanked: 0 Times
Default

Quote:
Originally Posted by SPARKled View Post
But an F2 opening of the aperture of a P&S will be way smaller than an equivalent focal length F2 opening of a SLR lens. I have a P&S which has a 2.8 - 4.0 lens and the 2.8 of the P&S is no where close to the opening of an el cheapo 18-55 aperture at 5.6. So comparing F values just as printed values is irrelevant. So a F2 of a P&S will not be equivalent to a F2 of a SLR lens at the same focal length. If this was not the case then how do you explain the the lens of superzoom P&S of say 500mm zoom fits a body of a size of just larger than a palm of a human hand, while the 500mm f4 behemoth of a SLR is a huge bazooka.
APETURE is not affected by anything, its a fixed hole

Now for the reason of size of the lenses.

Pro lenses are deisnged to have minimal CA and Distortion. In order to reach this level, lens elements need to be slimmer, slimmer elements mean the elements need to be both big in diameter and hence needs to be further away from each other. Which means longer and wider lenses.

Also lens size is affected with Sensor size. Sensor size means the imaging circle a lens needs to have to cover the sensor.

About P&S with super zoom, its called TC or teleconvertor. a single lens element placed between Lens and sensor means sensor will see CROP of the actual imaging circle. A 2xTC will only see 50% center of the actual lens. Since only middle of the front element is used at this point, Front element`s size is reduced since it doesn`t need to be bigger.

Ultimately the result is very compact mechanism for zoom but it also means higher CA, higher Distortion and worse of all smaller APETURE or Bigger F No. which in turns means SLOW lens. APETURE mechanism is smaller since it will never need to reach F4 let alone F2. Don`t forget 90% of the Super zooms also lie about effective APETURE. How companies go across this is by advertising higher Mp count and also advertising THEORATICAL APETURE not effective.

Good example of this is PENTAX LTD lenses, each lens has different EFFECTIVE APETURE and is advertised as EFFECTIVE APETURE.

I hope i have explained it properly and it makes sense.

Quote:
Originally Posted by SPARKled View Post
I still feel thats one hell of a lucky 50 1.8 to have survived that and no amount of ABS plastic and the works could have saved it from a direct impact of that magnitude.
It definately is.
it_inspector is offline   Reply With Quote
Old 3rd November 2009, 15:11   #1880
BHPian
 
Join Date: Oct 2009
Location: Bangalore
Posts: 507
Thanked: 57 Times
Default

Quote:
Originally Posted by bmw_m5_titus View Post
With the 1000d you get the non IS lens, no?

And I too feel the Sigma 70-300, is slow and noisy, and the images lack sharpness.
The canon 55-250is or nikon 55-200vr are better options.

No, you get with IS.
Proving the highlighted sentence would be greatly appreciated .
livyodream is offline   Reply With Quote
Old 3rd November 2009, 15:33   #1881
Senior - BHPian
 
rkbharat's Avatar
 
Join Date: Sep 2006
Location: Gurgaon/New Delhi
Posts: 1,590
Thanked: 606 Times
Default

Thanks buddy, that is a very wise advice, BTW just a quick Q, does it has the LiveView, I mean screen to see and take pics, instead of view finder.

80K for D90 that also with 18-55 is wrong, its available at 67K with 18-105 with jjmehta.com, 56K in grey market

Quote:
Originally Posted by livyodream View Post
Ive been using Canon 1000D since 6 months (Yeah its my 1st DSLR) and i'm prett much impressed with the pictures.
Many of 1st time DSLR buyer have a mentality that buying a Costly cameras will make them a good photographer or will yield a better picture. I dont think it really happens though ive never used a top end cameras (Still an amateur ).
My theory goes like this -spend reasonable amount of money on the Camera, spend on lenses according to the necessity.

Ive been using Sigma 70-300 with Canon 1000D and im pretty much impressed with the image quality and the cost too. (cannot upload the picture as im still a newbie)

Nikon D90 costs close to 80K in BLR with 18-55 lens (which has live view). Compare it with Canon 1000D which comes for 26K with 18-55 lens. Upgrade the lens to sigma 70-300 (Which I did) costing 14K more. All inc - not more than 40K.
Once you are on that level that I'm done with entry level DSLR then put it on sale on Ebay and buy an EXPENSIVE camera.
No office meant.
rkbharat is offline   Reply With Quote
Old 3rd November 2009, 15:50   #1882
BHPian
 
Join Date: Oct 2009
Location: Bangalore
Posts: 507
Thanked: 57 Times
Default

Quote:
Originally Posted by it_inspector View Post
I respectfully disagree. Walking 15kms at 2am in chilly winter with 55kg of camera equipment on my back to take shot. That is the low resolution version, if needed i can provide full resolution version. Its actually a mix of 16 shots.


And i can show you what a Nikon 200-400mm f4 can do, or for that matter Canon 400mm f2.8 can do.

What`s your point??? I am asking since you cannot compare a camera technique and final image quality just by price and reach.
First of all, that is an amazing picture . I can imagine how difficult it was to capture.


The DSLR Thread-_mg_3217.jpg

An example.


I never said the other lens cannot do. Who is comparing here. All im saying that even with low budget one can achieve what they have in mind.

Quote:
Originally Posted by rkbharat View Post
Thanks buddy, that is a very wise advice, BTW just a quick Q, does it has the LiveView, I mean screen to see and take pics, instead of view finder.

80K for D90 that also with 18-55 is wrong, its available at 67K with 18-105 with jjmehta.com, 56K in grey market

Yes it does. That is why i did not comapre with D40 or 60 (which comes in this price range) as it does not come with live view (AFAIK).
Sorry on the price part, was just a guess .

Last edited by Jaggu : 3rd November 2009 at 16:14. Reason: Removing the picture from quote, readability. Thanks
livyodream is offline   Reply With Quote
Old 3rd November 2009, 15:58   #1883
Team-BHP Support
 
Jaggu's Avatar
 
Join Date: May 2004
Location: Bangalore
Posts: 17,633
Thanked: 7,169 Times
Default

1000D is a good choice but if you can stretch a bit go for 450D, without B&W but genuine ones are good VFM
Jaggu is offline   Reply With Quote
Old 3rd November 2009, 15:59   #1884
BHPian
 
SPARKled's Avatar
 
Join Date: Aug 2009
Location: Navi Mumbai
Posts: 925
Thanked: 294 Times
Default

Quote:
Originally Posted by it_inspector View Post
APETURE is not affected by anything, its a fixed hole

Now for the reason of size of the lenses.

Pro lenses are deisnged to have minimal CA and Distortion. In order to reach this level, lens elements need to be slimmer, slimmer elements mean the elements need to be both big in diameter and hence needs to be further away from each other. Which means longer and wider lenses.

Also lens size is affected with Sensor size. Sensor size means the imaging circle a lens needs to have to cover the sensor.

About P&S with super zoom, its called TC or teleconvertor. a single lens element placed between Lens and sensor means sensor will see CROP of the actual imaging circle. A 2xTC will only see 50% center of the actual lens. Since only middle of the front element is used at this point, Front element`s size is reduced since it doesn`t need to be bigger.

Ultimately the result is very compact mechanism for zoom but it also means higher CA, higher Distortion and worse of all smaller APETURE or Bigger F No. which in turns means SLOW lens. APETURE mechanism is smaller since it will never need to reach F4 let alone F2. Don`t forget 90% of the Super zooms also lie about effective APETURE. How companies go across this is by advertising higher Mp count and also advertising THEORATICAL APETURE not effective.

Good example of this is PENTAX LTD lenses, each lens has different EFFECTIVE APETURE and is advertised as EFFECTIVE APETURE.

I hope i have explained it properly and it makes sense.
Hmm Lets see. From what I concur from your explanation is that a F4 500 on a superzoom lets in exactly the same amount of light as F4 on a Nikon/Canon prime, even though it may have more more CA and distortion.

Just look at this thread
SLR vs P&S: Nikon SLR Lens Talk Forum: Digital Photography Review

So from the second reply in the thread it surely means that the aperture (opening to let light in) of the P&S will be much smaller than that of the same aperture value of the DSLR. Infact he says that F2.8 on the P&S is still smaller than the opening at F8 in a DSLR. How can this be explained? Also say that there is no zoom at all in the P&S so going by the logic explained by you, F2.8 on this camera will be the same opening diameter as a F2.8 of a SLR lens for that focal length?

What you are also saying is that zooms in all P&S cameras including the non super zooms use TCs to reach different zoom focal lengths from the base focal length and none of them ever use actual lenses to get the required zoom?
SPARKled is offline   Reply With Quote
Old 3rd November 2009, 16:35   #1885
Team-BHP Support
 
navin's Avatar
 
Join Date: Mar 2004
Location: mumbai
Posts: 22,367
Thanked: 3,779 Times
Default

Quote:
Originally Posted by Samurai View Post
What is the cheapest weather sealed (body+standard zoom) cost with Canon?
40D+17-55/2.8 IS (around $1600-1800)

Quote:
Originally Posted by it_inspector View Post
Personally i had beer spilled on my D3+70-200mm, i just washed it under tap and its all fine.
You are a bold man to have washed the lens & body. On second thoughts I might have done the same becuase any damage due to liquid was probably already done and beer if left unwashed would get sticky and gum up the mechanicals.

Quote:
Originally Posted by it_inspector View Post
Everyone is going to take me wrong in sense to Canon 50mm f1.8 mk2. So i am going to layout the comparison in terms of quality and quality only. I bet Rs.10L you can run a Safari over Nikon 50mm f1.8/Zeiss f1.4 and these can still be used after a bit of cleaning and removing filter ring. Canon, well just drop it from 5feet and it comes out in 2 parts

I respectfully disagree. Walking 15kms at 2am in chilly winter with 55kg of camera equipment on my back to take

I don`t get the point comparing DECENT P&S to BASIC DSLR. Its like comparing best sports car to BASIC formula one car. Its not a direct comparison. Please compare DECENT P&S to DECENT DSLR and basic P&S to BASIC DSLR and you will realise the real difference,

Now why ars DSLR`s better than P&S:-

1. Well first of all CONTROLS,
2. ISO, DSLR`s can produce pictures usable at ISO`s that NO P&S can achieve.
3. Burst rate
4. Battery
5. Lenses
Dude you really gotta be more careful with your lenses. First you get beer spilled on it then you run it under a 4x4 (he he just kidding).

Take a "Decent" P&S like the LX3 vs a basic DSLR like the Canon 350D/1000D or even the smaller Micro 4/3rds camera like the GF1 (Panny) and you will find that in the end is it bigger sensor that does make a difference. The GF1 can be pushed to ISO 800 something no P&S I know of is happy with.

Like you said it is exactly like comparing the best sports car (LX3) vs a basic F1 car (GF1). A dated 2005-6 F1 car will outrun the latest Lambo (or any other commercially produced sports car). The high ISO perfromance of DSLRs is due to this bigger sensor.

Panasonic Lumix DMC-GF1 Review: 25. Compared to (JPEG): Digital Photography Review

Quote:
Originally Posted by Jaggu View Post
The difference very evident once you view the shots on a big apple screen
My friends used to pooh pooh me carrrying around a DLSR kit while they had their handy P&S. Then came conditions where their P&S refused to take any image (low light - no flash allowed locations) or they only got blur (school sports and school theater). The final nail in the coffin was when I showed them the output (JPEG) of my DSLR vs their P&S on a PS3 connected to a 46" LCD.

They still wont carry a DLSR but atleast now they dont pooh pooh me when I do.
navin is offline   Reply With Quote
Old 3rd November 2009, 16:36   #1886
BHPian
 
Join Date: Mar 2008
Location: Melbourne
Posts: 27
Thanked: 0 Times
Default

Quote:
Originally Posted by SPARKled View Post
Hmm Lets see. From what I concur from your explanation is that a F4 500 on a superzoom lets in exactly the same amount of light as F4 on a Nikon/Canon prime, even though it may have more more CA and distortion.

Just look at this thread
SLR vs P&S: Nikon SLR Lens Talk Forum: Digital Photography Review

So from the second reply in the thread it surely means that the aperture (opening to let light in) of the P&S will be much smaller than that of the same aperture value of the DSLR. Infact he says that F2.8 on the P&S is still smaller than the opening at F8 in a DSLR. How can this be explained? Also say that there is no zoom at all in the P&S so going by the logic explained by you, F2.8 on this camera will be the same opening diameter as a F2.8 of a SLR lens for that focal length?

What you are also saying is that zooms in all P&S cameras including the non super zooms use TCs to reach different zoom focal lengths from the base focal length and none of them ever use actual lenses to get the required zoom?
I am going to take a last stab at explaining this

I used the TC example to show how massive zooms are achieved in compact form factor and in some cameras these are added and removed on the fly. I never said every Super/Ultra zoom uses TC.

There is more CA and distortion because of smaller and thicker lens elements. And remember the actual size of Aperture is not that big. It seems big to us because it gets magnified when we view it through front/rear of a lens.

Also primes are different to zooms in base design and hence are lighter and are sharp.

About aperture well please google Micro Thirds system and then google nikon/Canon to Micro Thirds adapter. Here you can see sensor size is reduced by 50% or a factor of 2, yet each lens has SAME aperture size. Similarily in a P&S size of Sensor and lens is reduced.

After this the only choice i have left is to simply open up a P&S and compare the aperture size manually and document it for you guys.

Thanks
it_inspector is offline   Reply With Quote
Old 3rd November 2009, 16:45   #1887
Team-BHP Support
 
tsk1979's Avatar
 
Join Date: Feb 2005
Location: New Delhi
Posts: 22,910
Thanked: 15,572 Times
Default

Aperture size is dependent on lens, not sensor

Aperture area(actual area) = Pi*(f/2N)^2

So if you take lens 1 lets say Canon 50mm F1.8 and open it at 2.8, the area of the hole will be different from the area of the aperture hole in Sigma 500mm F2.8.

However if you are talking about amount of light, it will be same whether is a hassalbad or a P&S

For example if you open the shutter for 1/80 seconds, with aperture at F4, the amount of light energy reaching the sensor will be same, whether its a P&S or a DSLR.

So if you take a LX3 set aperture to F4, and take a shot at 1/100 at 28mm(35mm equiv) at ISO 100, the histogram will be more or less identical to a Canon 350D shot with 18-55mm set to F4 and ISO 100 at wide end.

Confused eh? See the actual physical area of the hole will change, but amount of light will be same for same apertures.
So if your light meter says Shoot the scene at ISO 100 F1.8 Shutter 1/100, you have to shoot the scene with this setting irrespective of the camera.

Last edited by tsk1979 : 3rd November 2009 at 16:49.
tsk1979 is offline   Reply With Quote
Old 3rd November 2009, 16:50   #1888
Team-BHP Support
 
Jaggu's Avatar
 
Join Date: May 2004
Location: Bangalore
Posts: 17,633
Thanked: 7,169 Times
Default

All this is becoming greek and latin to me! for me i just compose the shot inside my head and then shoot using camera. Dont even have Photoshop or GIMPS
Jaggu is offline   Reply With Quote
Old 3rd November 2009, 16:54   #1889
BHPian
 
Join Date: Oct 2009
Location: Bangalore
Posts: 507
Thanked: 57 Times
Default

Quote:
Originally Posted by Jaggu View Post
All this is becoming greek and latin to me! for me i just compose the shot inside my head and then shoot using camera. Dont even have Photoshop or GIMPS

I swear. Everything just flew over my head.
But that opening up the camera and showing is something i wanted to see .
livyodream is offline   Reply With Quote
Old 3rd November 2009, 16:56   #1890
BHPian
 
Join Date: Mar 2008
Location: Melbourne
Posts: 27
Thanked: 0 Times
Default

Quote:
Originally Posted by tsk1979 View Post
Confused eh? See the actual physical area of the hole will change, but amount of light will be same for same apertures.
Sorry i did got confused between physical size and amount of light.
it_inspector is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
DSLR Video Discussion Sankar Gadgets, Computers & Software 129 18th August 2017 19:07
On a Temple Visiting Spree! Returned with only 1 wish. Need a DSLR! mclaren1885 Travelogues 23 27th July 2007 11:21


All times are GMT +5.5. The time now is 04:09.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks