OK, I have just come from observing a discussion that started off civilly, but eventually degenerated into abuse and counter abuse, and it really wasn't necessary, as there are good resources to look at to gain knowledge on this. What am I talking about? .... Protective measures for your front element.
It makes sense that folks will want to avoid destroying the lenses which they laboured long and hard to afford. However there has always been a debate as to how effective, or not, such measures are. One simple approach is to consider how much it would cost in trouble and dollars (or whatever currency) terms if the front element was seriously compromised. In anything but the very cheapest lenses, I would submit that it will cost more than that of both a filter and a lens hood - Canon please note, you will stop people complaining if you would include a lens hood with ALL lenses, not just the majority of L glass - it's just a piece of plastic, after all.
Logic suggests that one should establish exactly what threats the lens can suffer, so we can assess the counter-measures that are appropriate. Good research practice suggest seeking information from respected and authoritative sources, as well as one's own (but possibly limited) experience.
Now, I could just ask GPT4, but it has a habit of making things up, so I went back to seeking sources that have gravitas. One such is the team at Lens Rentals: after all they have to deal with supplying thousands of the things to a wide range of users, who take them to all sorts of places, and do all sorts of things to them. So, here is one reference I found that is worthy of your review:
Lens Rentals | Blog: How to Ruin Your Camera and Lens
So from this is what I have come up with:
- Direct Impact damage - i.e. the sort of thing that happens if something hits the front element head on. The risk here is the shattering of the front element, and/or displacement of it and other optical components.
- Oblique impact damage - often when a camera is dropped, it may topple to place the lens lowest and may strike something solid (like planet earth), but not perpendicularly. The risk here is as above but also the distortion of the lens focusing or (when appropriate) zoom mechanism
- Environmental Damage - from sand, paint, salt, chemicals or something hot. All of these can damage the front element, but they can also insidiously work their way into the mechanism and wreak havoc with those components. This may not be sudden, but it can be every bit as destructive.
There are several approaches to mitigate this:
- Never take your camera out where it might suffer harm - that seems a bit restrictive to me, but whatever...
- Use a lens hood
- Use a glass filter on the front of the lens
These last two are where the "fun" and debate begins... This swings back and forth between always and never for each, and then folks break out the abuse and weaponry. It seems to be one of those topics that inflame passions, people take positions, and let fly at the opposing views.
So, let's try to approach this in a structured manner...
I'm going to leave option 1 out of the discussion - there may be some folks who collect optics as museum pieces or paper weights but I suspect they will be in the minority.
Luckily, doing my research, I found there are other article from our oracles at Lens Rentals on the subject of protection. The first one was written in Dec 2016: Lens Rentals | Blog and that has been further updated later in May 2018: Lens Rentals | Blog, finally in June 2017: Lens Rentals | Blog Roger Cicala was a busy chap!
Now, I would encourage you to read all of these because they are inciteful, and have some great technical data, but if you want the spoiler, here it is:
Lens hoods will protect the front to some degree from head on impact and some oblique strikes because they should project ahead of the front element. Note: this does not apply to someone attacking your lens with an ice pick or being shot at with a bullet - just saying... The plastic will take some impact and just flex, deform, or in worst case crack, but that should reduce the risk. What a lens hood does not protect from is environmental damage - as listed above. Usually there is no impact - these are mostly abrasions, chemical or electrical issues.
OK, so is a filter always necessary? - inevitably it depends on the expense of your optic and how or where you are using it. If one works in a controlled environment, then the risk of damage or degradation is much less, but if one works in a harsh environment - and that can be any coastal area, for example, then the risk increases. Using a lens in sandy, particularly blowy conditions can push dust across the lens and remove the coating, and I have had molten metal eat into a filter when doing a shoot in a foundry - so really, its about risk mitigation not absolutes or guarantees.
A filter can, under certain circumstances, actually provide some protection from oblique impact. When travelling with a lens, attached to a camera body, in a padded holster, as I went through airline security the chap dropped the whole thing from about 200mm (8") onto the conveyor. When I checked the filter was completely shattered and the metal ring was so distorted as to require to be sawn off. However, tests indicated the lens had not suffered damage or were the optics displaced. The good news was it was cheaper and faster to replace the filter than send the lens off for repair, which would have impacted my photo shoot. I actually had a lens hood attached but it was reversed for travel in the padded holster - go figure...
Without doubt putting a rubbish piece of glass in front of your beloved lens is not going to help your images. Logic suggests that one should stick to name brands and higher cost units, but Roger's tests indicate that this may not be a hard and fast, universally correct rule. Some of the modest-priced filters performed quite well optically and a couple of name brand units were less than stellar. Also, getting filters on the cheap as kits with a ton of other (likely useless) accessories off box stores, or on line, is not the most reliable source for anything, but particularly optical components. So, conventional wisdom says buy from a reputable dealer after (as always) doing your research - and I don't mean by asking all of social media what to get...
There is going to be a cost/benefit equation here. If you are using a really cheap lens, it might not be worth putting an expensive filter in front, but as Roger commented in his later articles, the sad news is that the cost of replacing the front element of a lot of lenses has skyrocketed massively in the last few years to the point that a good quality filter is now much more of an economically-viable consideration.
So, what do I do? I use both, as required. To me it's all about risk management, not guarantees.
cheers, TREVOR
The mark of good photographer is less what they hold in their hand, it's more what they hold in their head;
"All the variety, all the charm, all the beauty of life is made up of light and shadow", Leo Tolstoy;
"Skill in photography is acquired by practice and not by purchase" Percy W. Harris
