Doubt on my A7 iv + Sigma 150-600 mm sports

[jhamers]

I recently upgraded my aging Nikon setup to this combo and I'm having some concerns about the quality and fit of this combo. As I haven't used a lens this size, this could be down to a lack of experience. So, i'm facing two 'issues' that make me wonder what's going on:

• There is a bit of play on the mount/connection. I know this is a heavy lens, but each time Iuse the zoom ring, you feel it hit a stop in that direction; turn the zoom ring in the other direction and you feel the same in the other direction. It is very minimal and you can hardly see it, only by focusing really hard on the connection between the lens and body, you can see this happen. I know that they can't lock this into place like a vault door, but i'm worried that this happening constantly will cause a lot of wear and tear on the mount?
• Another issue (hopefully unrelated) is that I had quite a big piece of something (not dust) on the sensor after a walk. I only have one lens so far, so I haven't been swapping lenses but still something end up on the sensor. The paranoid part of my brain is telling me that the minuscule movement in the first point is creating small pieces to break of and land on the sensor. Or would it be normal for some stuff to travel around and end up on the sensor (after two weeks of usage)?

 

[Pieter]

Question 1) In my experience also, some lenses have the tiniest bit of play along the torsional axis. I guess this is normal as the locking pin in the mount is cylindrically shaped rather than conical. Shouldn't cause any wear on the lens/mount because those are metal parts and the play is really really small.

Question 2) The play in the mount does not cause any wear on the lens/mount so shouldn't cause material to come loose. It also does not cause a leak that might let dust into the sensor chamber. Whatever your something was, it'll likely be a one time issue if you don't notice any other loose/broken stuff on your camera/lens. Do note that the risk of dust, debris or muck on the sensor is considerably higher with mirrorless cameras than with your trusty DSLR, as there is no mirror in the way to protect your sensor. Best to train yourself in changing lenses with the mount facing downward to reduce the risk of collecting dust. Also, always bring a rocket blower to get dust off your sensor. Again, use the blower with the mount facing down, so any loose dust falls out of the camera.

[jhamers]

The sensor cleaning kit is on its way :-). 

[FunWithCameras]

As you say, this is a rather heavy lens. You need to support the lens, rather than hold the whole thing up by the camera body - that's why there is a tripod mount on the lens. Otherwise you are putting more stress on the mount - bear in mind, too, that the length of the lens means that there is quite a bit of torque at the mount. Supporting the lens should soothe the paranoid part of your brain 🙂 

I owned an earlier version of the Contemporary version of the lens, and it extended a long way (around 10cm). That level of extension meant that it sucked air into the lens when it extended, and pumped it out again when it contracted. This means that you can get it sucking in dust and some of that will end up inside the camera. I start with a blower bulb before resorting to sensor swabs.

It is a good lens, and very useful for longer shots. 

[Pieter]

12 minutes ago, FunWithCameras said:

I owned an earlier version of the Contemporary version of the lens, and it extended a long way (around 10cm). That level of extension meant that it sucked air into the lens when it extended, and pumped it out again when it contracted. This means that you can get it sucking in dust and some of that will end up inside the camera.

Not quite... Lenses usually blow out air the same way they sucked it in. If they suck in from the front, they blow out to the front. There's usually no gap around the rear element that blows air into your sensor chamber. Unless the rear element moves while zooming: then it needs to depressurize the sensor chamber.

Edited April 24, 2023 by Pieter

[Veres Deni Alex]

10 hours ago, Pieter said:

Not quite... Lenses usually blow out air the same way they sucked it in. If they suck in from the front, they blow out to the front. There's usually no gap around the rear element that blows air into your sensor chamber. Unless the rear element moves while zooming: then it needs to depressurize the sensor chamber.

true

[jhamers]

11 hours ago, FunWithCameras said:

As you say, this is a rather heavy lens. You need to support the lens, rather than hold the whole thing up by the camera body - that's why there is a tripod mount on the lens. Otherwise you are putting more stress on the mount - bear in mind, too, that the length of the lens means that there is quite a bit of torque at the mount. Supporting the lens should soothe the paranoid part of your brain 🙂 

I do support it with one hand obviously as I'm sure you can't just hold the body alone 🙂 But still obviously if you hold the lens with one hand, twist the zoom ring while holding the body with your other hand there is some force on the connection; unless you pull/push the zoom obviously.

[harrypm]

Was looking around for somthing unrelated and found this thread welcome to Sony! here is a 5 year user braindump.

Sony E mount has been a "okay" system with a decent payload support.

(There grips still have no securing pin like the Minolta 7D and A7/A9 film bodys orignally had and it does wiggle and shear the powder coat off with enough load/use...)

However after using adapted glass from metal adapters to the first party LA-EA3/LA-EA4 & Techart servo adapters and now the MC-11 with my 150-600 EF, the E-Mount metal bayonet does start to bend slightly its not made of anything strong just magnesium alloy, while the mount on the frame of the bodys are pretty reliable the mount on optics and adapters will start to bow ever so slightly after a few years of using the LE-EA4 with the Sigma 24-105 I had to take a hammer to it as heavy zooming was rattling it in the mount slightly, but by hammering out the bayonet around like 0.3mm of bend was corrected it went back to being perfectly tight like new.

Cleaning on bodys however it should be noted take the bottem plate off, if you ever get serious debris in the body it will just fall out with light air puffs and tap the side never shake up/down to get real debris out of sony bodys, if it lodges into the IBIS or shutter thats 100USD in parts and a 2~3 week wait from Aliexpress not a fun experance but shims can come lose if the body is knocked hard enough.

Airblower is your best friend with mirorrless though, you can use clip-in filters if you need to isloate the sensor chamber from debris or fluids but these can cost optical issues in some cases but not many.

Cleaning lenses, use swabs & 99.9& IPA on the mounts people forget how much stuff builds up on them, then falls into the body/lens if there is no gasket rubber bands are your friend in very dusty situations.

Cleaning fluid is kinda a scam, really the coatings on the optical filter stacks (the glass that sits on the bare sensor) are ment to be cleaned off with 99.9% IPA as stated in the level 2 service manuals which everyone really should read if you go and buy a 2k+ value mechanical device lol, they are built like legos and use all standard phlips screws made to be human serviced with a layered build hence why the headphone ports are in the place they are now easy to swap out in the field in 10min or less.

[Springfield-Photo]

The sensor on DSLR cameras were given no protection by the mirror as this has gaps either side of it where dust could get past. The sensor was, however, protected by the shutter which was closed. You can set the shutter to close when you turn the camera off on the A7 IV and I would advise that you set this option. You should always turn the camera off when changing lenses as the charge on the sensor is a magnet for dust.

The item to set the shutter to close is on the setup menu, item 12 setup option, Anti-Dust Function, Shutter when Pwr off.

As for the slight movement, this isn't that unusual as the tolerances can vary slightly in manufacturing. I have never experinced any wear showing up on any camera that I have used as a result.