Push-pull lenses and sensor dust question?

Are Nikon dSLR sensors or other brands for that matter more susceptible to dust with older push-pull zoom lenses? My collection of lenses are mostly variable aperture lenses and I'm thinking about acquiring the 35-70 and 80-200 f/2.8 lenses based on the good reviews I've read. These lenses are also very affordable compared to more modern lenses with a twist zoom mechanism. They would be used with my D800 and/or the D7200.

I briefly owned both of these lenses. I knew the 80-200mm had seen heavy use before I got it, and it had a more than average quantity of dust. The 35-70mm was bought off eBay with history unknown, and it had almost no dust inside. However, its exterior was equally clean, so maybe it just hadn't been used much.

 

Anyway, I don't think it matters much whether a zoom is push-pull. Two-ring zooms can also suck air and dust in when you zoom, especially if the cam ratio is high. The 24-120mm f/4G is an example.

I LOVE push/pull zooms, but only on manual focus cameras, where it is a 1-touch/single ring, push/pull zoom+focus. My 2 favorites are the 43-86 and 80-200 f/4.5.

My 75-300 AF is a push/pull zoom, but focus is a 2nd ring so the AF mechanism is separated from the zoom ring. That seems to defeat the purpose of a push/pull zoom. Although, it is easier to zoom the entire zoom range with a push/pull than with a rotating ring. Think shooting sports on the field.

 

Warning, you NEED to handle the lens first. My 75-300 has stiction, where I think the grease has accumulated and somewhat dried out, so when the zoom is at the end positions, it is stuck. When pushing or pulling from the end positions, a significant extra force is required to move the zoom ring. This makes the lens difficult and a pain to use in situations where you want to zoom freely. I have tried a few other old P/P zooms and some of them have that stiction problem. This is fixable with a CLA, but a CLA on a zoom is likely to be be expensive (the cost is to recollimate the lens when reassembling it).

With push/pull zooms, you have the external zooms where the front element moves forward and the lens gets longer, and the internal zooms where the lens does not get longer. I think the breathing is more of a problem in the external zooms, just as it is with the 2 ring zooms.

Back to the OPs question.

I think some Canon cameras have a sensor clean mechanism that shakes the sensor when you turn the camera off.

My Nikon D7200 does not.

The big question is how much the issue matters. - You'll get the most dust during lens changes. So as long as you haven't enough bodies to never change lenses at all, you'll face the dust problem.

some Canon cameras have a sensor clean mechanism that shakes the sensor when you turn the camera off

Or on. - Similar to be found in Pentax / Samsungs, Fujis... - I think Olympus came up with the idea for the old (pre micro) four thirds stuff. - I have no idea how valuable that technology is for real, since it equals domestic feather dusters or air compressors that surely move dirt around but don't get it it out or trapped inside some kind of container.

I haven't used anything push pull excessively on digital but would look for other reasons than the dust issue, to rule those lenses out.

Back to the OPs question.

I think some Canon cameras have a sensor clean mechanism that shakes the sensor when you turn the camera off.

My Nikon D7200 does not.

 

I suggest that you check page 321 of your user manual... :D

( it tells you about the "dust removal system" in your D7200, which all recent Nikon DSLR models have..)

 

As for the "Dust" isseu with push pull zooms, i find that those push pull zooms sometimes can act as a "Dust Pump" , in the analogue era this would mean sometimes a spec of dust on your film, in the digital era it can ad up in dust in the mirror box / on the sensor since each image is projected on the same sensor surface, where film"moves on"to the next photo-sensitive surface whit each picture..

Indeed, the D7200 does have the shaking system, as do MOST recent Nikon DSLR models, but just for the record, this feature was apparently dropped in the D3400,

Thanks guys, I had not dug that far into the menu.

I can't speak to recent low end cameras, but the sensor shaker showed up on DX with the D300 and I think with the D700 on FF.

 

The D300 actually makes an annoying squealing sound when the shaker is running-I've had a couple of D300 and D300s bodies and all have done it. My D800 is silent.

 

FWIW, you can set the shaker to clean at start-up, shutdown, both, or only on demand. I set mine for shut-down as it can add a second or so delay to start-up.

Appreciate all the comments. I'm ordering the 35-70 from KEH to try one out. If I like it i'll order the 80-200 next.

I have made this observation: If the front element/front housing of the zoom rides in and out, there is air pumping going on. Example: 36-72/3.5 E series zoom.

If the the front/front element does not move, there is hardly any air exchange through the mount. Interior elements sliding back and forth do not pump air to or from the outside. Example: 80-200/4 AiS

I have made this observation: If the front element/front housing of the zoom rides in and out, there is air pumping going on. Example: 36-72/3.5 E series zoom.

If the the front/front element does not move, there is hardly any air exchange through the mount. Interior elements sliding back and forth do not pump air to or from the outside. Example: 80-200/4 AiS

MM Not sure if that is entirely true ..

If a group of elements within the lens is moving forward an backward, ther can be still a "pumping"action i guess ( Two pumping actions, one in frot of the moving group andone behind it..)

If the lens woul be totaly airtight ( not many are...) without the chambers withinn the lens being connected , then overpresure and underpresure in the two chambers arounf the moving group would result, if the lens is not airtight then the lens would still "breath" environmental air i guess.

I think you're all forgetting that a DSLR has a mirror and shutter in front of the sensor while all this 'pumping' is going on. Any dust shifted about doesn't even reach the sensor.

 

And pressurised air will flow towards where it can escape to a lower pressure. That's not going to be toward the sealed back of the camera, but toward the eyepiece, lensmount, or back towards the cracks in the lens where it got in.

 

LiveView is a different matter.

Edited April 26, 2018 by rodeo_joe|1

Shifted dust doesn't go straight to the sensor, but you can certainly suck things in through a lens and have it float around the mirror box until the shutter opens. The mirror slap then disturbs things again. The shutter isn't a reliable protector - otherwise I wouldn't be so good at getting dust on sensors. Generally dust is something I do my best to avoid (especially having been in a house full of cat hair until recently), but I also try to avoid small apertures, which helps with small dust. If I see hairs on my viewfinder I tend to make a point of shifting them in the hope of minimising the odds of them falling on the sensor.

Two-ring zooms can also suck air and dust in when you zoom, especially if the cam ratio is high. The 24-120mm f/4G is an example.

 

I can confirm that lens is a pretty good reverse-vacuumcleaner.... switching primes regularly seems to cause less tiny dust spots than using this lens a lot, in my experience.

 

That said, with any decent raw editor, spotting the dust and cloning it over to a series of photos is a trivial task, so while annoying, I don't get too worked up about some dust since it's not ruining an image and doesn't cost ages to deal with.