UV Filter Photography Test

12 Myths Every Photographer Should Know

In Photo Basics by Jim Harmer

Two weeks ago, I found myself grabbing my DSLR, putting on a lens with no filter since that destroys image quality, putting it on a tripod and using a cable release to take the landscape photo, putting the camera in mirror lock-up mode for a night photo, turning on long-exposure noise reduction, and covering the optical viewfinder to prevent light leaks.  I was doing it right.  It was technical photography perfection.

And then, I snapped.  I suddenly realized that I do all of those “technically perfect” things simply because I've been told they improve the image.  Like most photographers, I was doing what other people told me to do.  But the mark of a true expert is personally testing everything and not falling into the trap of believing the “old wives tales” or, in this case “old photographers tales.” So, I set out on a personal quest in the last two weeks to test everything in my workflow to weed out any useless steps.  I want to reduce my photography to the simplest and purest forms so that I can come here to Improve Photography and teach you how to enjoy your photography more.

Thank you to the kind members of our community who helped with this article by submitting myth ideas.  If you'd like to join us, please LIKE  our Facebook Fan Page.

#1  A clear UV filter degrades image quality (True, but it's not as bad as you'd think)

UV Filter Photography Test

If you look closely, you can see a slight yellow tint in the whites of the photo with the cheap UV filter on.  Click to enlarge.

First of all, since this was a bigger test, I wrote a separate article just explaining my findings of this test and how I performed my testing.  Here's a link to the full article, or simply read the summary of my findings below.

For years I have heard photographers say that putting a clear UV filter on a lens degrades the optical quality.  It's usually a claim made without showing any proof.  Many photographers use UV filters on their lenses to protect the front element of the lens from being scratched, but other photographers are too afraid to use one because it might reduce the sharpness.  These photographers often make comparisons to putting cheap tires on a Ferrari, or say that it is ridiculous to put a cheap plastic filter in front of a $2,000 lens.

Believing this to be true, I have never used a clear UV filter on my lenses. I didn't even own a UV filter to test this belief, so I bought one from Amazon.  I didn't just buy any UV filter.  I bought the cheapest junkiest one I could find. I figured that if this junky filter didn't degrade the quality, then any UV filter would be fine.  But one UV filter wasn't enough.  Dustin Olsen, who now works with me on Improve Photography, also tested the belief with his UV filter using a different camera and different lens. In testing, neither Dustin nor I were able to see ANY reduction in the sharpness of the lens–even zoomed in to 100% with multiple examples.  HOWEVER, while there was no reduction in sharpness at all, both Dustin and I found that the UV filter produced a minor color cast on the image.  Also, the UV filter undoubtedly caused more lens flare when shooting toward a bright light source.

Takeaway from this photography test: There is no reason to panic about using a UV filter.  It just doesn't make hardly any difference unless you're shooting into the sun.  The color shift was actually very slight and I would think that nicer filters would not have this problem.  What this test revealed to me is that UV filters do cause some problems, but it has nothing to do with the sharpness and the reduction in image quality is only very slight.  I'll keep my UV filters off the camera unless the situation arises where it would be handy (like shooting in a very dirty environment or shooting near the ocean near sea spray).


#2 The native ISO (often ISO 200) produces less noise than ISO 100 (MYTH!)

Native ISO test

Very tough to see without zooming in really tight, but there is very slightly less noise in the ISO 100 sample.

Most photographers believe that ISO 100 will produce the most noise-free image; however, some photographers say that the native ISO of all Nikon DSLRs is 200, so they hypothesize that ISO 200 will produce less noise.  So which is it? I was really anxious to test this myth because I wasn't sure of the answer myself.

Please note, as has been pointed out multiple times in the comments below, that these tests were done with the D7000 and a Canon Rebel.  These cameras have a native ISO of 100, which automatically debunks the myth that the native ISO of all Nikons is 200–it is not.  I'd love to see a reader test out this myth with a different Nikon that has a native ISO of 200, but I haven't seen anyone send in samples yet.  My point here is that it is incorrect to state that all Nikons shoot with less noise at ISO 200.  That isn't true.

I have heard so many people talking about native ISO lately that I thought it actually might be true that ISO 200 is slightly cleaner than 100, but it just isn't true. I took multiple shots at 100 and 200 ISO and compared the results.  In every case, ISO 100 was slightly cleaner on my D7000 than the ISO 200 sample.  It may be that this is not true for other cameras, but I found the same result on a Canon Rebel. ISO 100 is (very slightly) less noisy than ISO 200.  I also tested ISO 125, 160, and 400.  It is a perfect scale.  The lower ISO produced the cleaner shot in every case.  There seems to make no impact on the noise on t he camera models we tested (Nikon D7000 and Canon Rebel T3i).  To see full-res image samples and read more about this test, read this article about the native ISO that I just posted to explain my methodology.

Takeaway from this photography test: The whole “all Nikons have a native ISO of 200” thing is… completely not true on the cameras we tested.  I would love to see some readers test this on their cameras so I can verify it on more models, but it looks like this is a total myth.


#3 The DPI or PPI affects the viewing size of the image on screen (MYTH!)

I already knew this was a myth before writing this article, but it is such a common misconception that I thought I would share it with the community.  Stated in the simplest possible terms, the pixels per inch of an image file doesn't matter one tiny bit when the photo is on your screen.  The photo could be 300 PPI or 3,000 PPI and it would look precisely the same.  Pixels per inch is merely a way to measure an image file.  You can change the number to whatever you want and the image resolution won't be changed as long as the total number of pixels in the image is not altered. For most photographers, this is probably a new concept.

If you're interested in learning all the pixelly details of this photography myth, then check out this awesome article from iStockPhoto.

Takeaway form this photography myth: Don't worry about the DPI until you're ready to print the picture.  The PPI has nothing to do with the viewing size of the image on your computer screen (although it does impact the file size).


#4 You can't adjust the white balance of a JPEG (MYTH!)

Photography myth about white balance

It is impossible to tell the difference in image quality between a photo white balanced using the RAW vs. using the JPEG.

Several months ago, I mentioned this myth in an article I wrote.  After the article, I had an exchange from an accomplished professional photographer on this topic.  He vehemently defended his position that a white balance change on a JPEG somehow produces an inferior image quality to a white balance adjustment made to a RAW file.  I emailed him two photos–one white balanced on the RAW, and one white balanced from the JPEG and asked him to identify the one with inferior image quality.  He couldn't.

Then, he changed his argument to say that it wasn't that a white balance change to a JPEG produces inferior image quality, but that it was really hard to do.  Nope.  Just open the JPEG in camera RAW (yes, it's possible to open JPEGS in camera RAW) or Lightroom and make the adjustment just exactly the same way as you would change the white balance on a RAW file.  No difference. I do not pretend that shooting JPEG is the same as shooting RAW.  There is a huge difference in changing the exposure, picture style, or many other aspects of a RAW file when compared to a JPEG; however, it frankly is not true that white balancing a JPEG is somehow inferior.  Don't believe me?  Test it for yourself and see. Same thing.

Takeaway from this photography myth: Obviously, there are huge benefits to shooting in raw; however, it simply isn't true that JPEG white balance adjustments somehow produce poorer image quality than RAW white balance adjustments.  There is a theoretical difference in the fact that the JPEG bakes in the adjustment and the RAW file can be changed losslessly, but if you can tell the difference between a photo white balanced from a JPEG and a photo white balanced from a RAW…. you have a better eye than I do.


#5 You need a commercial product for on-camera flash (MYTH!)

Gary Fong Lightsphere Review

I personally prefer the light from the tupperware and the Lightsphere over the flash bounced off the ceiling. The direct flash is nasty..

For the full run-down on this incredibly hilarious (and surprising) test, check out this separate post that I made to explain the whole thing.  If you're more of a Cliff's Notes kind of person, then here is a summary of the test. Most wedding and event photographers turn to a commercial product like the Gary Fong Lightsphere, or a host of other products for on-camera flash.  The purpose of an on-camera flash diffuser is to soften the light from a flash while staying portable to shoot a wedding reception, an event, or even your daughter's birthday party.  It helps soften the flash and produce a prettier quality of light.

I usually just bounce the flash off the ceiling for on-camera flash, but this doesn't work when you're in a building with very tall ceilings or you are outside at a party at night. One of the most popular on-camera flash diffusers is the Gary Fong Lightsphere.  I own one and have used it many times, but the Lightsphere costs $50!  In my opinion, that is way too much money for a hunk of plastic that sits on top of my flash. When I started working on this article, I thought…. hey, that DOES look like a piece of tupperware!  Naturally, I bribed my wife into posing (she's always a good sport) and compared the light quality of the Gary Fong Lightsphere to the light quality achieved from putting tupperware from the kitchen on my flash.  The results?  Indistinguishable.

Takeaway from this photography test: Save your money.  I could not see any improvement from using the Gary Fong Lightsphere when compared to the tupperware.   At first you might think that it would look ridiculous for a photographer to strap a piece of Tupperware to her flash and then shoot a professional job like a wedding reception, but you'll thank me when you have a handy bowl that you can fill with refreshments from the event.  You save $49 and you get a bowl of goodies from each event you shoot.  Fantastic!


#6 Mirror lock-up improves sharpness (MYTH!)

Mirror lock-up sharpness test

Mirror lock-up sharpness test

I really wanted this one to be true.  I have gone through the pains of using mirror lockup for my landscape photography for years.  I thought it was a main contributor to getting the sharp pictures that I try to capture.  After EXTENSIVE testing, however, I was not able to replicate any tiny bit of improved sharpness in the photos where mirror-lock-up was used.

For newer photographers, the mirror in your DSLR flips up very quickly when an image is taken and this movement can cause vibration in the camera.  Obviously, vibration can cause camera shake and reduce the sharpness of the image.  Mirror lock-up makes the camera mirror open, and then some amount of time is waited before the shutter is tripped.  This allows any vibration from the mirror flip to dissipate before the picture is taken.

It seems that mirror lock up provides no noticeable improvement in sharpness at any shutter speed as long as a sturdy tripod is used (which is advisable anyway).  One reader tested this with a really cheap $20 Walmart kinda tripod and did in fact see a difference.  I don't doubt it.

Click here for the full in-depth explanation of how I tested mirror lock-up.

Takeaway from this photography myth: Again, in theory, mirror lock-up sounds like a great way to reduce vibration and get sharper pictures; however, I tested this one over and over and was unable to see any improvement in photos shot with mirror lock-up compared to regular shots even when I was using long shutter speeds.


See! No difference whatsoever. Click to enlarge and see for yourself.  Even zoomed in to 100% 

#7 Saving a JPEG multiple times degrades quality (MYTH!)

I was quite surprised by this test.  It had always been my opinion that saving a JPEG multiple times degraded the image quality because each save of the photo means the JPEG is compressed again.  While I believe that this would be true if a lower-quality JPEG were saved out each time, it turns out that–after saving the same JPEG 30 different times–there was no noticeable loss in image quality.

The photo here was saved from a RAW file, and then I open the file 30 times, saved out a JPEG of the file, then opened the new file and repeated the process.  I did this 30 times and saved it on the highest quality in Photoshop each time. This myth actually quite handy to know.  Sometimes I shoot a photo, do extensive editing, and save out a JPEG.  If I later find a problem with the photo and want to make a little change, I always feel like I have to find the Photoshop file or start over with the RAW file.

Note that this testing was done using Photoshop's jpeg processor at full quality.  Obviously, different programs can provide different results and–obviously–if you don't save at the highest quality, then data will be lost.

I posted an in-depth explanation of this test as well as more sample images here.

Takeaway from this photography test: It is true that every time you save a JPEG, the algorythm runs compression on the file and you do lose some data.  That is undoubtedly true; however, this test reveals that you can do A LOT of saving of the JPEG and not see any VISIBLE reduction in image quality as long as you save at full resolution every time.  Obviously, if you save a smaller file, you'll lose more data.  If I can't tell the difference between a JPEG that has been saved out 30 times and the original… it probably isn't something to worry about.


#8 A high aperture is needed to get enough depth of field to take pictures of the stars at night (MYTH!)

Night photo

Star photo taken at f/2.8

This is another myth that I was aware of before testing, but which is so commonly believed that it is worth the mention.  Whenever I explain depth-of-field to a new class, I tell them that, when shooting a landscape, if you want to get the cool rock in the foreground as well as the sky in the background in focus, you need to use a high aperture to get full depth of field. So when I teach a night photography class, I usually find three-quarters of the class using f/22  so they “have enough depth of field to get the stars way out there in focus.”  This is when I sit them down and we talk about depth-of-field and focus.  If you believe this to be true, you're missing a big piece to the puzzle.

The truth is that most night photographers shoot the stars with an aperture of f/2.8 or f/3.5, etc.  How do we get the stars in focus with such a large aperture?  The answer is that the lens is FOCUSED on the stars.  Since the lens is focused to infinity much closer than the stars, it makes no difference whether you're shooting a star that is relatively close to Earth, or one that is light years further away.  If you enjoy night photography and want to learn more about shooting the stars and focus at night, you might enjoy my Night Photography eBook.


#9 IS/VR should be turned off when the camera is on a tripod (TRUYTH!)

It truly is amazing how photographers tend to divide over things so trite as whether or not image stabilization should be used when the camera is locked down on a tripod.  Most photographers say that you should turn off image stabilization (vibration reduction) on your lens when using the DSLR on a tripod to prevent the image stabilization from being too sensitive and moving while the picture is taken and thereby creating the movement that the feature is meant to reduce.

I have gone back and forth on this issue over the years until I discovered something.  It is something that male photographers have never seen, and if they have seen it, they have ignored it completely.  The women photographers have probably known this for years.  It's called the manual.  Not manual exposure and not the camera manual.  No, I mean the manual to your LENS!  Yes, it is good for something… actually, a lot of things. The answer to this myth is that it depends on the specific lens.  Some lenses have built-in the ability to turn image stabilization off automatically when the camera is locked down on a tripod.  Other lenses do not do this.  The only way to tell is to pull out your lens manual, blow off the dust, and find out.  As it turns out, almost all of my Nikon lenses do this for me automatically.

Takeaway from this photography test: It depends on your lens, but if your lens manual reveals what my lens manuals did, you'll be able to save time by simply leaving image stabilization turned on all of the time.


#10  You need to cover the viewfinder for night photography to prevent any light leaks (MYTH!)

Light leak on a DSLR

Night photography

This is yet another common belief among photographers that makes theoretical sense, but if you actually test it…. it becomes much difficult to see the problem.  When night photographers take long exposures of 30 seconds or more, they cover the optical viewfinder of the camera to prevent any ambient light from behind the photographer from entering through the clear viewfinder and showing up in the image. This makes perfect sense in theory, but despite my very best efforts to replicate this issue, I was unable to see the effects of the infamous “light leak.”  My friend and colleague Dustin Olsen also tested this on his camera with identical results.

Update: A couple people commented below that the light leaks DO change the camera's light meter.  While that may or may not be true, it left me wondering… WHY IN THE WORLD IS ANYONE TRUSTING THE LIGHT METER WHEN SHOOTING NIGHT PHOTOGRAPHY!?!?  The amount of light available at night is simply insufficient to use aperture priority.  It's all manual at night.

Takeaway from this test: I suppose if you're shooting a 5 hour exposure with a spotlight shining into the viewfinder, it would be possible to recreate the infamous light leak problem; however, even though I was trying my hardest to create a light leak, there was absolutely no difference in the resulting image.  As far as I'm concerned, the light leak myth is completely busted. For notes on how I tested this myth, I posted a full explanation of my light leakage testing here.


#11 Lenses are sharpest at f/8 (MYTH… with some truth!)

An aperture in a lens

An aperture inside a lens

For the full in-depth explanation of how I tested this and to see sample images at these apertures, click here.

Let's be clear.  There can be no doubt whatsoever that every lens has a “sweet spot” in which it produces the sharpest images.  Most photographers already know this, but haven't taken the time to test their lenses to see what aperture actually produces the sharpest results.

With the lack of testing, they latch on to the sage wisdom that f/8 is the sharpest aperture.  I often hear photographers so flippantly say “I'm shooting at f/8 for sharpness” that I thought it would be worth while to show the difference between different lenses and their sweet spots. Since this is a more involved test, I decided to dedicate an entire article this morning showing my findings from this test and how you can easily replicate it with your own lenses.  Check out the full article here.

Takeaway from this photography test: Do not flippantly assume that f/8 or f/11 is generally the sharpest aperture.  The truth is that it COMPLETELY depends on the lens.  You can spend the rest of your life guessing, or you can actually pull out your lenses and test it in 15 minutes.  To see my results and to learn how to do the test at home, check out the full article on this test.


#12 You won't share this page on Facebook or Pinterest, and you definitely won't click the Google+ button below (MYTH?)

Also, if you haven't joined the Improve Photography by LIKING our Facebook fan page, you're missing out on half of the fun!

Info About the Testing

You're more than welcome to disagree with any statement in this article and I'd like to hear what you've experienced that differs from my experience; HOWEVER (and it's a big however), please remember that I have ACTUALLY TESTED these myths.  So if you want to disagree, keep in mind that I probably won't give your comment much credence if I don't see a test you've performed showing me different results. I realize that there are possible deficiencies in each of these tests.  I get it–I'm not a scientist.  I would LOVE to see all of these myths tested on a wider scale, so if you want to put any of these myths to the test and send me your results, I'd be glad to see what you get.  I have, however, tested some of these myths (where applicable) with multiple camera brands/lenses/filters, etc.

About the Author

Jim Harmer

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Jim Harmer is the founder of Improve Photography, and host of the popular Improve Photography Podcast. More than a million photographers follow him on social media, and he has been listed at #35 in rankings of the most popular photographers in the world. He blogs about how to start an internet business on IncomeSchool.com..