MP size and hanging up pictures

[Fether]

I have a 18 MP camera and am curious as to how big of photos could I hang up on my wall before the resolution begins to really suffer... I understand this is pretty conditional upon preference, but just want some ideas

Edited March 5, 2018 by Fether

[bytebear]

I've done promotional posters that are 3'x6' and they look fine.  If you are looking for framing something for home, you should be fine going up to 18"x36" easily.  How big are you thinking?  And how much detail do you want?  Do you want to see reflections of things in a person's eyes?   Or an architectural photo where you can see the paint flakes on the siding?

[bytebear]

So, make sure things are in focus, so that when you zoom in, you can see the details you want to see, because the bigger you blow it up, the more details will pop.  Here's an example of what I mean.

Look at the detail of the raindrops when zoomed in.  You want to make sure they aren't out of focus if you go that detailed.

[Vort]

Assuming your 18 MP camera uses a 3:2 aspect ratio, it takes pictures of about 5200 x 3450 pixels. According to Wikipedia, the human eye has a resolution of one arcminute (a sixtieth of a degree), which is about a third of a milllimeter at a distance of a meter. So if you wanted to view your poster-size photos from a distance of no closer than a foot (30 cm), your pixel size would need to be no more than about a tenth of a millimeter. So 5200 x 0.1 mm = 520 mm = 52 cm, or about 20 inches wide.

So you could blow up your pictures to approximately 20" x 14" (width x height) and your eye would still not be able to make out the individual pixels at a viewing distance as close as a foot.

[Vort]

In practice, we accept a certain amount of graininess (= pixellation, more or less) when looking at pictures. So you could probably get quite a bit larger than my biological-based math above suggests. @bytebear sounds like he knows what he's talking about.

[bytebear]

That's true if you are printing in pixilation, but most photo printers blur the colors, so you can't see pixels.  It may be blurry, but won't look pixilated.  Even in the zoomed in, you can't really see the pixels, but you can see some JPEG residue, but that's a different issue.  I assume if you are going for full quality, you are shooting in RAW.  But even still, JPEG is generally good if you keep the quality ratio high.

Edited March 5, 2018 by bytebear

[Fether]

16 minutes ago, bytebear said:

That's true if you are printing in pixilation, but most photo printers blur the colors, so you can't see pixels.  It may be blurry, but won't look pixilated.  Even in the zoomed in, you can't really see the pixels, but you can see some JPEG residue, but that's a different issue.  I assume if you are going for full quality, you are shooting in RAW.  But even still, JPEG is generally good if you keep the quality ratio high.

Another question. Are there any good free photo editing programs? I’ve used adobe photoshop a lot while I’m school, but don’t really want to buy it.

[Fether]

Oh and I have a Cannon EOS rebel T6

[lostinwater]

1 hour ago, Fether said:

I have a 18 MP camera and am curious as to how big of photos could I hang up on my wall before the resolution begins to really suffer... I understand this is pretty conditional upon preference, but just want some ideas

Probably depends on a lot.

My (probably incorrect) understanding is that you can resolve 18MP on a tiny sensor or 18MP on a large sensor (ie pixel pitch/density).  The more pixels you pack on a small amount of sensor real estate, the more noise you introduce.  And that noise becomes more visible when you blow up an image.  You can also have a horrible lens that focuses a bunch of 'bad' light (lacking a better term) onto a reasonably good 18MP sensor.

i think the results you are going to see when you blow up an image will be impacted quite a lot by those two factors.  The former will especially degrade if you're shooting at higher ISO, or doing a lot with the shadows in post processing.  

i'm a fan of Lightroom, but it's not free (trial aside).  

Google used to charge for their Nik Collection - but i believe it's free now - or it was a while back.  Been quite impressed with that.

https://www.google.com/nikcollection/

Below are some articles worth checking out

https://www.imaging-resource.com/PRODS/canon-t6/canon-t6-image-quality.htm#print-quality

https://www.digicamdb.com/specs/canon_eos-rebel-t6i/

Edited March 5, 2018 by lostinwater

[Vort]

12 minutes ago, Fether said:

Another question. Are there any good free photo editing programs? I’ve used adobe photoshop a lot while I’m school, but don’t really want to buy it.

I have no personal experience, but acquaintances have said very good things about GIMP. As its name suggests, it's an editor for Gnu/Linux, but has versions for Windows and Mac, as well. Apparently, it's robust and full-featured.

[bytebear]

I love GIMP, and use it for almost all of my photo editing.  It's free and does most everything Photoshop does.  It also has excellent color correction features for old washed out photos or pictures where you didn't do the white balance correctly.  Great for minor touch ups, or image correction (band aid tool for getting rid of spots).  I've used it to get rid of pimples, scars and added sleeves and lengthened skirts.  I even added my nephew to the family photo of his 2nd birthday, since he was napping at the time. 

[bytebear]

1 hour ago, Fether said:

Oh and I have a Cannon EOS rebel T6

I have Canon as well.  Rebel is a great choice for a first camera. Lenses will be where things get expensive.  One tip is that some camera stores have rentals.  I use Samy's in California. They have excellent weekend deals and have rented everything from lighting to cameras to lenses.  So if you want to try out a lens or are looking to buy a new camera and you want to try it out first, rent it. The only catch is they do take full price deposit on your credit card, but they give it back.

I am also lucky because there is a Canon repair center near by that used to do free cleanings, and I have had things fixed there under warranty.  And Canon does free seminars on photography. They used to have a great one in Catalina.  Free transportation to the island, free tee shirt and free seminars.  And I would make a weekend of it.  Those were the days.

Edited March 5, 2018 by bytebear

[NightSG]

12 hours ago, Fether said:

I have a 18 MP camera and am curious as to how big of photos could I hang up on my wall before the resolution begins to really suffer... I understand this is pretty conditional upon preference, but just want some ideas

I've done 8x12" (don't get me started on the evil of 8x10" becoming a standard) from a 2MP camera that looked excellent.  And that was a low light cave photo.  Beyond a certain point, it's more a matter of getting the shot right than the number of pixels.  Somewhere, I should still have the negatives from a big pile of film (35mm and 120) and scans of those and other shots from a 10MP DSLR.  Once they're scanned in at around 9600DPI, I have to really look to figure out which camera took what, (except that the 6x6cm 120 is obviously square - and the 6x9cm frames do tend to show a crisper image at high zoom.) and even then I get mixed up on the desert scenes.  (Carlsbad Caverns, the surrounding area, and Fort Davis all got mixed together since I didn't take a daylight tank to process the film before returning.)

FWIW, it seems to be a generally accepted limit on some of the hybrid-process (generally, scanning negatives) photography groups that around 16MP is the point of strongly diminishing returns when scanning 35mm film frames.  I know some of the pro wet drum scanners tend to go to 30MP, but that's partly because folks want every detail of the film grain preserved.  

[zil]

13 hours ago, Fether said:

I have a 18 MP camera and am curious as to how big of photos could I hang up on my wall before the resolution begins to really suffer... I understand this is pretty conditional upon preference, but just want some ideas

If you're not planning to use a commercial printer, then the answer is that you can print it as large as your end-user printer is capable of printing (generally 11x17) - assuming you're using a reasonably high resolution (as opposed to the camera's lowest resolution).  If you don't know that your camera is capable of different resolutions, go into its settings and look for the picture quality settings - there may be high / medium / low type words, but it should also show you the actual resolution in pixels.

If using a commercial printer, the best way to figure this out is to contact the commercial printer you plan to use and tell them the resolution of the image.  Commercial printers generally print at 300-350 dpi (or higher), so at that point, it's a matter of knowing your photo's resolution and doing some math.  In my experience, commercial printers are happy to answer this question.  By way of example, the printer I use has templates here:

http://www.gotprint.com/content.html?id=posterDownloadTemplates&rightMenuId=rightMenu&footerId=bodyFooterStyle6

And if you download the JPG and look at the resolution, that will tell you what the resolution of your images needs to be in order to print at the specified size.  (This is based on 350ppi = 350dpi - I think they do this because (a) it will give you a high quality image, and (b) it's easy for laymen to figure out without more complex rules which would still allow a quality image, but you have to consider more variables.)