Macro-photography

Quite interesting how Smartphone cameras take such attractive phopgraphs. It's a combination of technologies. First the sensor is carefully matched to the lens, and is a modern type that collects more light than early models. The lens is very simple and although of high-quality, it makes no attempt to correct aberrations or to provide zoom or any of the other features that make big camera lenses complicated and expensive. Instead, zoom, focus and lens corrections are all done in software after the photograph is taken, possible because smart phones contain a powerful computer. The image software is supported by the phone's other sensors, notably an electronic gyroscope that detects shake and compensates it out. The software also applies several algorithms to make the image look better. In addition to automatic contrast adjustment, edge detection is used to sharpen lines, and various tricks pulled to improve images by popping the colours, optimising for flesh tones when a face is recognised, and adapting to bright sunshine, twilight, night shooting and extreme close-ups.

There's always a down side! A smart-phone's in-camera processing is designed to make images look good at the expense of accuracy, which enables ordinary folk to quickly take good looking photographs with almost no fuss. But the images are more or less a lie! Information recorded by the lens is dumped by the camera in favour of bling. The cameras work extremely well for casual photography but blowing up their results to A4 and above reveals lots of unwanted processing artefacts. Doesn't matter most of the time, but there are many exceptions.

Keen photographers and professionals usually want to be in complete control of their cameras and any processing they choose to do later. Images as captured by their cameras might be distinctly bland, but all the optical information is intact and the photograph may be manipulated later without losing anything. The photographer has access to many image processing techniques and can produce the best possible results, either in terms of accuracy for technical photographs (metallurgy) or heavily manipulated for aesthetic reasons (hot chicks). The disadvantage is it's not quick, cheap or easy. In particular, because the goal is to capture the maximum amount of information about the original subject, the entire optical system has to be the best money can buy.

Dave

Edited By SillyOldDuffer on 20/05/2020 14:17:30

On Monday, walking along the canal at Macclesfield, I noticed this little fellow:

.

.

Not sure if he was planning to use the ‘parachute’ for descent, or to offer it to his lady-friend as a bouquet.

Of course, I immediately wished that I had my camera [and tripod, and focus-slide, and light-diffuser] with me.

But I managed to take this ^^^ with the ‘phone: a cheap Samsung Galaxy : GT-S7580

.

Here’s a crop from that image:

... which, as Dave rightly says, is full of processing artefacts and also has restricted dynamic range.

But, all things considered, I was quite pleased.

MichaelG.

.

As promised: **LINK**

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4031072/

MichaelG.

.

Note: Dave might like to admire the simplicity of the mass-market lens

[ see Figure 2 on p4 of the document ]

I think you are doing down just how powerful phone cameras are, the quality of the compression is comparable to a DSLR shooting JPEG. Their main flaw is small pixels, which limits dynamic range and low light capability.

I use either my phone or a bridge camera for all my 'standard' photography, including for MEW and my books and have used photos off my phone as covers on MEW, last one being issue 291 which does show some artefacts, but it was taken indoors without flash and is cropped from a much larger frame.

I only shoot RAW for my astrophotography, because I have to tease out very faint details.

Example - right click and select 'view image'. You'll see this image at native resolution 1:1.

It's cropped out of this:

Taken on my old Nokia phone, several years ago, any sign of objectionable artefacts?

Neil

Macro used to be defined as the film image being larger than the subject. Magnification loses its meaning with digital, especially phone cameras as the sensors are so tiny as its pixel resolution that matters and the sensors pixels are so much smaller than even the finest grained film.

A 7 megapixel image will give a 300 dpi A4 image. (3000 x 2400 pixels). Even the puny (for today) 13MP camera in my now-outdated Moto G5 can stand being blown up to an A3 double spread at 300dpi, comparable to 35mm film.

The size of the object that can fill that image space depends on the optics, not the sensor and tiny apertures (as in phones) are much less prone to aberrations that plague larger lenses.

Thanks for the info Roy. I remember may late father (Entomologist) showing me his dissecting microscope. He was working on fruit flies (Bactrocera) and showing me how he examine the specimen under high magnification. He placed the flies in a plastic container and placed in a fridge. He also takes pictures via the microscope but I remember it was on film. He do his own film processing and also loved photography.

Michael, i'm trying get to understand the concept. I can relate to sensor/film image projection and telling myself all the time that phone camera would be totally different.

SOD, thanks for sharing your thoughts on this. It helps clear some confusion I have.

Thanks for the input Neil.

I took some pictures via my phone camera. Could not upload it here as I realise it is in IMG not JPEG. How do I get to upload it here? Are all phone cameras IMG? 

Edited By RAPHAEL VAL GOLEZ 1 on 20/05/2020 17:26:15

Edited By RAPHAEL VAL GOLEZ 1 on 20/05/2020 17:28:20

.

This may help: **LINK**

https://newatlas.com/camera-sensor-size-guide/26684/

Many camera phones have pixels of about one micron square !

Happy to discuss further, either here or by P.M.

MichaelG.

Raphael, my phone makes and stores images in .jpg format. The .img file suffix usually denotes a disc image file. iPhones apparently use .png. My guess would be that the phone image is being "translated" by some software on your PC (assuming you are using a PC to upload the image). I usually look at, resize, crop or otherwise edit my phone images using GIMP before using or uploading them. GIMP will happily deal with most image formats and is free software similar and as powerful as Photoshop.

John

Edited By Journeyman on 20/05/2020 17:59:11

Thanks for the link Michael, very good information.

Thanks John, I will give it a try.

So I did change my camera to see the difference. I usually use my D700 FX with my macro lens. This time I used my D90 DX crop sensor. I have more room on the focusing distance though it feels different to my D700 in some ways. Took a range of subjects I can find in the garden and selected appropriate size from a pea size spider to as small as a tip of a ball point pen spider. I cropped it to get more closer. I'm surprised at how the D90 captured the image on the sensor. This are all hand held and did my best to hold my breath while shooting in macro.

I'm waiting for my extension tubes and I will also try reverse rings attachment.

Very nice pictures Raphael, even the rather scary arachnids!

Neil

https://imageshack.com/i/pmDUNP4aj

Drosophila head. Olympus MVX10 stereo.

This continues to be a great thread Raphael !!!

Thanks for your insights Dave. I’ve pondered for some time about how phone cameras are able to produce images with such amazing results.

In the late 50’s I was ‘cutting-my-teeth’ on a Leica IIIf with three lenses and a document copier with three extension tubes. In those days, a resolution of 96 lines per millimetre was the sort of standard quoted. I have no idea how that relates to pixels. Perhaps someone here will explain?

What at first is hard for me to digest is the amount of effort and technology which went into precision lens grinding, and how many elements were needed in the 50mm – f2 Summitar; seven from memory. Now we see a miniscule lens apparently producing similar resolution. Would any of these lenses be injection moulded?

I can appreciate the scaled-down pixel size, but how are the lenses made with (I imagine) an essential high degree of accuracy?

Not about macro, more about printing large from Nigel Danson’s phone camera images, is this ...

**LINK**

Sam

Edited By Sam Stones on 20/05/2020 22:02:37

Looking like a round solid, our brains tend to flip what we see with what we are more familiar, thus presenting a mind-confusing illusion.

Sorry Peter, in reality, it is actually a hole through what remains of a sandwich of metal ‘shims’ after an EDM wire-cutting exercise.

Crammed and riveted between two pieces of 1/16" (1.5mm) gauge plate (CSt) are several hundred pieces of thin 0.003" (0.08mm) stainless steel (SSt).

Lying about over time (more than 30 years), the high carbon steel (gauge plate) has developed interesting rust spots.

Rather than disrupt this thread, I’ll start another about the rusting.

Sam

Hi Sam, very good teaser, I was trying my hardest to see a negative side to this (you know the one, where the picture of a cast of a face, appears to stand outwards) but I just could not see anything. Even now I have to really think about it, doesn't help as you have shown the big picture from the opposite angle, cleaver.

Regards Nick.

.

Very briefly, Sam ... “96 lines per millimetre” actually means “96 line pairs per millimetre” and a line pair is one black and one white on the resolution test chart. This sort of resolution is adequate for all but the finest silver halide film-stock.

Importantly ‘resolution’ in this context is the ability to just distinguish that a blurred blob contains two distinct items.

[ for background reading try searching ‘Airy Disk’ and ‘Rayleigh Criterion’ ]

A digital sensor, by comparison, can have pixels as small as one micron square, and, to do justice to that the lenses need astonishingly high resolution.

If you haven’t done so already ... have a look at the paper I linked earlier. [14:05:29 U.K.]

MichaelG.

.

Edit: See also

https://en.m.wikipedia.org/wiki/1951_USAF_resolution_test_chart

Edited By Michael Gilligan on 20/05/2020 23:08:02

.

**LINK**

Hi Michael, that's the one, makes one wonder if you know your own mind.

Regards Nick.

Several years ago, I risked buying a couple of achromatic close-up lenses (250mm and 500mm) for my Canon Legria G40 HD camcorder. Although authentic Canon lenses threaded 58mm, I couldn’t be sure they would be fully compatible accessories in an optical sense, that was the chance I took. Later tests proved to be what I considered acceptable results.

An early opportunity to test one of them came when I was fortunate enough to find this dragonfly to take home. Thinking it had died, I placed it on the nearest silver birch branch at a convenient height. As it happened, it was still alive and actually flew off later.

It was early morning and perhaps cold enough to limit the creature’s movement but not mine. I dashed inside, grabbed the tripod and the 500mm close-up lens.

I chose to run the camera on video, later selecting the single frames seen here.

Head and shoulders?

But what about the saw-tooth edges?

What purpose do they serve?

Any clues?

Sam

The rose, perhaps not quite MACRO in the accepted sense, was barely 2cm across. It sat about 30cm off the ground in a near abandoned shady part of the garden.

The background was a not very inspiring old wooden fence, so it was an opportunity to open the file up in Photoshop.

I couldn’t find a suitable background to slip in behind it so ‘all-black’ seemed an appropriate alternative. With a bit more jiggery pokery, I gave it a lift into pseudo 3D by hiding the edges of the frame behind the petals.

There’s so many tricks you can do in digital photography, it’s becoming mind-blowing.

Sam

Please excuse my muscling in on your thread Raphael. Close-up photography can be fascinating.

Having chosen this for my avatar, I have pondered over the colours.

There are colour bands both distinct and diffused. Are they a result of different gases, different temperatures, and/or do they show limitations imposed by a stepped colour gamut within the image file?

Sam