Cropping & pixels

[hobodan]

Hi all, I have a question.

I have a 24mp sensor - if I shoot at 200mm with 24mp & crop the image to a 100mm equivalent; is that going to produce a copy with the same quality as a 12mp sensor shot at 100mm?

Also - is there any benefit to reducing my image size from 24mp to 12mp in camera? (apart from saving memory space)
I'm pretty sure it won't increase the ISO ability as the pixel size doesn't change? Is this correct?

Just wanted some clarification without assuming

Thanks

 

[seriousrikk]

If you shoot at 200mm you can't crop the image to 100mm equivalent. Maybe you are thinking shoot at 100mm and crop to 200?

Anyway, to answer your question, no it won't. Not sure exactly what it would be, much complex maths to work that out! But it is not as simple as it looks!

 

[hobodan]

Sorry, yes did mean the other way.

 

[Photodiva]

Why not just shoot with a 100mm?
Can't see any benefit in using only half your pixels, you paid for 'em after all. Which camera do you have? Only time too many megapixels is a problem is when they're stuffed onto a tiny compact camera sensor.

 

[hobodan]

I have the nex7.

It wasn't because Im necessarily wanting to shoot at 100mm & crop to 200mm. I'm just trying to understand the affect of resolution & focal distances with regard to pixels!

 

[gblades]

If you crop an image rather than using a longer lens then you are asking a lot more of the lens.

 

[mortimerhill]

If you shoot at 100mm and crop to the equivakent of 200 mm, you're down to 6mp not 12mp as you're only using 1/4 of the original image

 

[HoppyUK]

If you crop an image rather than using a longer lens then you are asking a lot more of the lens.

Yes, and in this case you're also running low on pixels too.

If you shoot at 100mm and crop to the equivakent of 200 mm, you're down to 6mp not 12mp as you're only using 1/4 of the original image

Yes. Basically, if you're looking for image quality then cropping is the last option when you've run out of optical reach and foot-zoom too.