Optical illusion

by Stefan Fletcher May. 06, 2009 4318 views

I decided to conduct a two-fold test tonight on:

1. The resolving power of my favourite lens

2. My resolve in not drinking the subject

The only optical illusion is the one where you think the whisky is still in the glass when you read this.

As camera manufacturers still believe that more pixels = more sales, the number of pixels captured by cameras increases. My Canon 5D mk II boasts a resolution of 21 million pixels and will soon be overtaken by a Sony. One problem is that sensor size doesn’t increase. This means sensor manufacturers are cramming more active pixel sensors into the same space, which leads to extra noise and additional noise reduction measures, some of which reduce image quality. Compact cameras and the cameras on mobile phones are the worst offenders, boasting up to 5-8 Mp. The sensor, incidentally, is smaller than a thumbnail.

To give a sense of scale: unless you own a professional (i.e., expensive) computer monitor, the maximum resolution on your screen is 1.5 Mp (not 8), which means your graphics card dumbs things down so you can see your pictures. An 8 Mp camera will provide professional-quality photo prints up to 8 x 11“ (A4). Anything more is overkill. Basically, if you’re looking for a camera these days, resolution is the weakest argument camera vendors can field (and also means either the vendor doesn’t know what s/he’s talking about or thinks you don’t).

The other problem – and this is really a crime, in my opinion – is that amateur / enthusiast grade SLRs are being sold with crap ”kit" lenses that simply can’t resolve to the level of image quality required by 12 Mp+ camera bodies. Your images may not be out of focus. They foisted a naff lens on you. Buy a cheap compact boasting 10 Mp resolution and kiss goodbye to sharp pictures. Canon, Nikon and Sony have all done this. Look at all the new 30 mm lenses introduced today for crop-sensor cameras as a tacit (and expensive) acknowledgement that kit and cheapo lenses haven’t kept up with camera technology. In fairness, I must point out that specific Ricoh, Panasonic and Sigma compacts are notable exceptions to this con.

Resolution is the lens' ability to generate a ‘sharp’ image on the sensor. This isn't the correct definition, but Wikipedia's attempt is a little too technical. Basically, take a picture and blow it up. How sharp does your lens resolve? As you can see from the above, this lens is sharp. I traded in my kit lenses a long time ago and I've only just added this paragraph to the post about an hour since I took the shot, so I can't duplicate the experiment with a compact or my iPhone (and besides, I've drunk the whisky).

So, the above were a test of how ‘sharp’ my favourite lens is. They are all crops of the same picture. The only thing I did after some tonal corrections was scale everything to 800 pixels in Photoshop. I had hoped I could make it interesting, but my composition wasn’t very good. The radioactive green stuff is not this morning’s sample from yesterday’s post, but white truffle oil caught by my yellow curtains.

My resolve failed as far as the whisky was concerned. The wine bottles should be reasonably safe – for now.

This blow-up of a shot taken from about 50 cm away. To give a sense of scale, the scratch on the whisky glass is approximately 3 mm long.

This is the full-frame shot using a 45 mm TS-E lens, which explains why the subjects ‘stand out’. All of the above are just progressively smaller crops of the above image. The underexposure was intentional. No, honest. The TS-E is a manual focus lens and for this kind of test (if you're thinking of doing the same), I strongly recommend using the live view function on your camera before drinking the subject.

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There are 12 comments , add yours!
Lynda 12 years, 1 month ago

I read that you have scottish ancestry- surely it's sacrilege to put ice in whisky?That's what my other half thinks (he's scottish).

12 years, 1 month ago Edited
Robert Moffat 12 years, 1 month ago

Interesting - though I suspect I would have ended up drinking both and having a bad head! I am jealous of your lens!

12 years, 1 month ago Edited
Piyali 12 years, 1 month ago

I agree with you on that--I hate the kit lens that came with my camera--and oh your poor subject--gets gulped up everytime it stands in front of your camera I suppose..

12 years, 1 month ago Edited
Eric J H Joyce 12 years, 1 month ago

Nice.......................

12 years, 1 month ago Edited
Illicite Abumdance 12 years, 1 month ago

What nice shots of alcohol! Very good, Stephan!

12 years, 1 month ago Edited
Hong S 12 years, 1 month ago

can i have one?

12 years, 1 month ago Edited
Paul Mcclure 12 years, 1 month ago

Okay, I'm too lazy to read everything right now. But I do get the general idea...I think. In any case, neat set and it looks like your subject survived.

12 years, 1 month ago Edited
Jarvo J 12 years, 1 month ago

Thanks for the lesson. Given that I only ever look at pictures on my computer monitor, and that was the top of the range Tomy - My First Computer when our kid was a babe in arms, I think I can safely scale down to something more usable. Tommorrow is operation camera obscura - all I need is a shoe box and a darning needle. Seriously though, this explains why the pictures from my old Canon compact 4mp look every bit as good as from my new one 8mp. Plus that has the advantages of being quicker to upload and taking less memory.

12 years, 1 month ago Edited
Marsha 12 years, 1 month ago

Hmm....very interesting and thanks for the information. I dropped and "disabled" the kit lens that came with my camera. Instead of getting it repaired, I ordered another lens - worked out, I guess. If you're not drinking the wine....please send it over ;)

12 years, 1 month ago Edited
Kecskemétiné Nelli 12 years, 1 month ago

Congratulations to your favourite lens..
I have a four-year-old 5 Mp Panasonic compact (first and only) thing and I have never thought of changing it. I didn't know why. From now on I will know.. =D

12 years, 1 month ago Edited
Brian 12 years, 1 month ago

Thanks for saving me the wine, I prefer that:) I am one who is currently using a kit lense that came with my Nikon. It's all I have at the moment. Time to start saving up.
What do you use as a backdrop in your shots?

12 years, 1 month ago Edited
Michael Sakowicz 12 years, 1 month ago

Thank you for putting this into words. I have known this for a while and wondered why camera makers keep marketing the ultra-high-end multi-million-billion mega-pixel cameras to amateurs and pro-sumers, but the answer as it always is - is the moo-lah. So, hey! everyone, stick with what you got! It's good enough. =)

12 years, 1 month ago Edited
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