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Old 23rd March 2011, 14:57   #6796
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Well the answer is if I cropping butterfly from the scene shot with a 7d and a 5d, I will get better cropping result from a 5d.

You are right that there will be more pixels per mm on the sensor but not on the photos. Agreed that there are more pixels to mm on aps c sensor but the sensor itself is much smaller. With the aspect ratio kept the same, 21 mp output will always more lines of resolution than 18 mow on the photo - simple maths. You are not cropping a picture on a sensor, but you crop the picture on a computer in post processing. So while there are morelines per mm on the sensor for an aps-c the sensor itself is smaller. So on the whole the 21 mp picture will have more lines of resolution and is hence better for cropping than an 18 mp one.


We can continue to discuss on this, but in terms of viewing mtgs to compare lenses, I will never rely on jpegs.raw is the way to go. Keeping the camera constant and lens as a variable, raw is the way to go.
Cheers
Prasad
Typed on iPhone - apologies for any mistakes.

Last edited by bbkp : 23rd March 2011 at 15:23. Reason: Add more text
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Old 23rd March 2011, 15:43   #6797
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Sometimes it makes me laugh. Looking/reading at the fights and realising majority of the facts are just missing.

Everyone needs to understand the fact that everyone is UNIQUE and so is the situation they are in. One might need FF for low light images while other might need it for slimmer DOF and other might need it for UWA lenses.

I know of a wedding shooter who went to D3s solely to use PC lenses to full shift/tilt (all of nikon PC lenses will hit flash/prism on every nikon body except Dx series).

off topic @ bbkp, next time your in Sydney, visit Vanbar (Melb vanbar guys are way better tough), I promise you will love the range of lenses and films and chemicals. Its one of the places that still has Rodinal and also IR film in the fridge
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Old 23rd March 2011, 16:13   #6798
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Sometimes it makes me laugh. Looking/reading at the fights and realising majority of the facts are just missing.

Everyone needs to understand the fact that everyone is UNIQUE and so is the situation they are in. One might need FF for low light images while other might need it for slimmer DOF and other might need it for UWA lenses.

I know of a wedding shooter who went to D3s solely to use PC lenses to full shift/tilt (all of nikon PC lenses will hit flash/prism on every nikon body except Dx series).

off topic @ bbkp, next time your in Sydney, visit Vanbar (Melb vanbar guys are way better tough), I promise you will love the range of lenses and films and chemicals. Its one of the places that still has Rodinal and also IR film in the fridge
Well I am currently in Sydney. Will make it a point to visit the place. Sounds really interesting. And relax I don't think anyone is fighting here. It was just a healthy debate :-)
Cheers
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Old 23rd March 2011, 17:22   #6799
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BBKP do the math once more , Where ever you crop does not matter the proportion matters , Yes it is simple math so just do it .

Let me help you with few hint.

5D MK2 pixel density per sq mm 21.1/(36X24) MP/sq mm now you project it on a 10X screen get 21.1/(36X24) pixels if you crop it by half you get 21.1/(36X24) * 1/2 pixels screen size used for editing does not matter here so you do on PC or not is immaterial.

Suppose if you put a masking tape around the 5D MK2 sensor such then you only 22.3 X 14.9 centre area is exposed then you are creating a APS-C sensor and that has less pixel density.

An APS-C 7D has 17.9 /( 22.3X14.9) again you project and edit on a whatever size sceen the number remains same.
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Old 23rd March 2011, 18:09   #6800
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BBKP do the math once more , Where ever you crop does not matter the proportion matters , Yes it is simple math so just do it .

Let me help you with few hint.

5D MK2 pixel density per sq mm 21.1/(36X24) MP/sq mm now you project it on a 10X screen get 21.1/(36X24) pixels if you crop it by half you get 21.1/(36X24) * 1/2 pixels screen size used for editing does not matter here so you do on PC or not is immaterial.

Suppose if you put a masking tape around the 5D MK2 sensor such then you only 22.3 X 14.9 centre area is exposed then you are creating a APS-C sensor and that has less pixel density.

An APS-C 7D has 17.9 /( 22.3X14.9) again you project and edit on a whatever size sceen the number remains same.
There you go - you pretty much answered the question. If I take photograph with a full format, the size of the picture is 36 x 24 mm on the sensor. Whereas the picture taken on a aps-c sensor will be 22.3 x 14.9mm. Agreed that there are more pixels per each mm of the aps-c sensor but the full format picture is much bigger. All in all, it has 3 more mps which can be utilized in cropping.
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Old 23rd March 2011, 18:50   #6801
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off topic @ bbkp, next time your in Sydney, visit Vanbar (Melb vanbar guys are way better tough), I promise you will love the range of lenses and films and chemicals. Its one of the places that still has Rodinal and also IR film in the fridge
Vanbar lens prices seem way above the market rate here in Melb. Rentals should be worth a look.
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Old 23rd March 2011, 19:21   #6802
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.......In terms of deciding the lens, a lot also depends on the sensor - How much clarity does the sensor need? .....
Thats something I am hearing for the first time. Trying hard to understand the theory behind that.

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.......Shooting Jewellery involves working from very short distances and a wide aperature will help you isolate the jewellery from other items in the frame....
Again something heard for the first time. I dont know if anyone uses widest apertures for product photography, be it anything. The purpose of product photography is to put every mm of the product in sharp focus, which is usually attained by an f/9 or f/11 value. It might be different if conceptual shoot is the target, which is very rare in this line.

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......In terms of Sigma lens being better than Canon, I suggest you to still rethink because of the quality issues which Sigma has.......
Those days are over. Sigma produces very competing level of quality these days. I myself use a 70-200 f/2.8 and never got an issue. My friends have tested it whenever I am on a photo walk, got comments as its as equal as the Nikon or Canon counter part. I also owned a Sigma 18-50 f/2.8 lens which was very sharp, very quick and smart performer at any lighting condition.

Whereas Tamron is concerned, I hear words like 'focus hunting, noisy, blurry image, internal issues' and many more from whoever owned one or using one. To speak from experience, I also owned a Tamron 90mm f/2.8, it could never focus well on the auto mode than hunting back and forth like a crazy machine. I could not take it anymore, so it was sold to someone who would always use it on manual mode.

There are many points in your posts that are first hand info for me, so I am trying to figure out if things can be taken as facts When you guys debate on technical things, please also remember there are noobs like me who are struggling to understand many things but not able to !!
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Old 24th March 2011, 00:10   #6803
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There you go - you pretty much answered the question. If I take photograph with a full format, the size of the picture is 36 x 24 mm on the sensor. Whereas the picture taken on a aps-c sensor will be 22.3 x 14.9mm. Agreed that there are more pixels per each mm of the aps-c sensor but the full format picture is much bigger. All in all, it has 3 more mps which can be utilized in cropping.
Prey tellme how in real life ? Lets say I have shot super moon with 300mm lens which occupies a small center portion of the image not more then 5% of total area if I crop this out where I get more pixels.
Or a butterfly filling 20% of frame and i need to crop to give it a look of frame filling photo.
Do some calculation and also experiment before you shoot next response.
What matters is pixel per sq mm in case of cropping , Suppose if next generation FF has same pixel density as current top of the line APS-C then no issue but as of today that is not the case.

Last edited by amitk26 : 24th March 2011 at 00:11.
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Old 24th March 2011, 00:15   #6804
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Shaju, the Tamron 90 is macro lens, autofocus is bound to be slower on this type of lenses, good lens otherwise if you didn't have a bad copy, so manual usage is better off.

Regarding wide aperture macro, the below image was taken at f11, ignore the spots, i cleaned my sensor after this photo. Just to show how shallow depth is even at f11.
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Old 24th March 2011, 01:40   #6805
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Vanbar lens prices seem way above the market rate here in Melb. Rentals should be worth a look.
That is only on the website. Walk in store and the prices change. Then comes the fact, if you need serious advice or rare items, you cannot go past Vanbar.

If I remember correctly, Vanbar is the only store that was able to organise Lens-a-thon successfully. Lens-a-thon is a small 2-3day fair kinda thing but with literally every single lens manufacturer (image related) present with full offerings and one just needs to bring there body and go nuts. There were models and other stuff to shoot. Idea being, try the lens you may buy in future. I tried Nikon 200 f2 for the first time that day and to this day cannot shake it off.

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Those days are over. Sigma produces very competing level of quality these days.
His point was, Sigma is hit or miss kinda thing. Sigma has the worse Quality Control. You can search google for people who bought 50mm f1.4 and 30mm f1.4, its plain gamble to find perfect focusing lens or front/back focusing lens. Its gone to the point, where consumers go to store and keep checking the lenses till they find a good copy.

Sure one can adjust focusing but then it should not be needed in the first place.

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Originally Posted by amitk26 View Post
What matters is pixel per sq mm in case of cropping , Suppose if next generation FF has same pixel density as current top of the line APS-C then no issue but as of today that is not the case.
Crop cameras will ALWAYS have higher pixel density than FF counterparts. Take it rule of thumb.

Let me put it this way, Higher pixel density improves final image and Lower pixel density improves final image. Point is how its printed/displayed/blown.
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Old 24th March 2011, 01:41   #6806
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Prey tellme how in real life ? Lets say I have shot super moon with 300mm lens which occupies a small center portion of the image not more then 5% of total area if I crop this out where I get more pixels.
Or a butterfly filling 20% of frame and i need to crop to give it a look of frame filling photo.
Do some calculation and also experiment before you shoot next response.
What matters is pixel per sq mm in case of cropping , Suppose if next generation FF has same pixel density as current top of the line APS-C then no issue but as of today that is not the case.
Now I know why there is this confusion. You are making an assumption that the shot is taken from the same distance to the subject everytime with both the cameras. Believe that is not how it would be though.
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Old 24th March 2011, 01:52   #6807
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@Shajufx

It is simple to understand. More pixel density on the sensor, more is capability to produce sharp images even when zoomed to the max. However, the lens needs to be capable enough to be providing a level of sharpens that will distinguish between each pixel else the sensor's capabilities are not getting utilized. This willresult in blotchy images - blotchy when zoomed out.

Shooting jewellery would need sharp focussing on anything that is possible at f9 -f11 range. I agree with you. But there are rimes when you would need good dof to isolate the subject. Hence taking an f2 is better because it can be stepped down to f9. The otherwY round is not possible though. Hence better to go for f2.

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Old 24th March 2011, 05:10   #6808
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@amitk26,

I believe the confusion arised from the fact that you were talking from a different point of view and I was talking from a different perspective. What I originally intended to say is high MPs come in handy when you want to crop the images. What you are saying is also right that if a picture is taken from the same distance from a subject, then, the crop factor of the camera plays a role and the crop sensor will allow for more pixel density around the subject.

Believe you are refering to crop factor of the crop sensor, which, for an APS-C works out to around 1.6. (Generally 1.6 for Canon and 1.5 for Nikon, Sony, Pentax) That is if a 300mm lens is fitted to a camera with a crop sensor, the 35mm equivalent of that lens will be 300*1.6 = 480mm. This is exactly how camera manufacturers are able to fit in mega zoom lenses into smaller bodies - it is made possible because of smaller CCD sensors. The real zoom range of the lens will be generally printed on the lens - something like - 6 - 60 mm. Whereas because the sensor is so small the 35 mm equivalent of it would be something like 35 - 350 mm.

@Shajufx,

Another point to consider apart from quality of the Sigma lens is the speed of the AF motor and time it would take to focus. Canon has some of the fastest focussing lenses - I have done a test to confirm this and the biggest USP for Canon is the speed at which the lenses can focus. Don't think that the Sigma lens with a standard AF motor can be a match. The Canon 15-85mm IS USM is super fast - Focuses at a speed faster than my eyes can wink - seriously good at that.

Haven't been to Vanbar in Sydney, but will go there. Sydney continues to mesmerise me with whatever it has to offer. This is taken a few years back, during my last visit with a Panasonic FZ-50. The effect of high pixel density on a small sensor is evident when you see the level of dispersion at the brightly lit places in the photograph - especially the blue light on top of the building the Luna Park below the bridge.
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Last edited by bbkp : 24th March 2011 at 05:13.
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Old 24th March 2011, 11:20   #6809
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Whether cropping will deliver better results on a full frame or a smaller sensor depends only on the proportion of the sensor the cropped image occupies. For example given same density and same lense the image size in pixels (bird?) will be same at a given distance, the only difference is that a FF sensor will have more scenery than a cropped sensor.

Now if both sensors are same MP, then a bird will have more pixels on a cropped sensor than on a FF sensor, and you will better off. In fact this is the reason why super telephotos give a larger image in cropped sensor (you get an instant magnification, or the focal length increase by cropping ratio!). It works exactly opposite for wide angles, where you get less width on a cropped sensor.

Regarding better lenses, a better designed lense will always give better image. The better part consists of robust construction, sharpness, bokeh, chromatic aberration and other distortions. You can observe and feel the "better" part, even though you may not be able to pin point exactly why. Carl Zeiss has a range of lenses in Canon and Nikon mounts which are at least twice as expensive as native ones. These lenses are in great demand by professionals, so they must be doing some thing right.
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Old 24th March 2011, 11:40   #6810
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Regarding better lenses, a better designed lense will always give better image. The better part consists of robust construction, sharpness, bokeh, chromatic aberration and other distortions. You can observe and feel the "better" part, even though you may not be able to pin point exactly why. Carl Zeiss has a range of lenses in Canon and Nikon mounts which are at least twice as expensive as native ones. These lenses are in great demand by professionals, so they must be doing some thing right.
Have you heard of cookie primes?

I bet once you use a C-mount Cookie prime, you will toss that Zeiss in the bin
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