My lens has a spot on it, is there anything I can do?

[Brian Drysdale]

The Canon series of telephoto lenses for stills cameras, the 300mm f2.8 and upwards, have be converted for use as cine lenses pretty much since they first came out. This involved changing the mount to the ones used on 16 and 35mm film cameras and are still found on high end digital cinema cameras.

The Canon 150-600mm zoom lens is also used.

[Chris Hurd]

Originally Posted by Brian Drysdale

The Canon 150-600mm zoom lens is also used.

Actually that's a Tamron or Sigma brand with an EF mount.

Canon doesn't make an EF 150-600.

[Ryan Elder]

Okay thanks. How is the Sigma for constant aperture or focusing while zooming though, not very good I'm guessing?

As for the lens I have now with the spot on, I am in the middle of shooting a documentary project with it and need to continue with it now. But what should I do about the spot? The store doesn't have any 300mm to rent for these telephoto shots. I suppose I could buy one, and then return it, since the store lets you try it out..

Or I could use the one I have, but I will have to go through every frame and try to cover up the spot later though.

[Josh Bass]

Do not do anything that requires to try to fix a problem frame by frame. After a second's worth of footage you will want to jump off a building.

[Ryan Elder]

Well I've done it before with a different camera once, where there was a spot on the sensor that I had to remove from someone face for quite a few frames. That's why when it comes to frame by frame work, I prefer to shoot at 24 fps, as it's the least amount of frames... What can I do then?

[Josh Bass]

Yes but that's "a few frames." Really think about what going through minutes of footage having to do that would be like.

[Ryan Elder]

Yeah I just don't know what else to do cause I need a long lens to capture the animals and cannot get another one in time on their budget.

[Josh Bass]

I mean ultimately it's up to you. I don't know how long final product is supposed to be or how much of it will be animal footage but just be warned it will be awful doing that correction. Maybe you can motion track or maybe you'll have a bunch of static shots so the spot doesn't move and you apply the effect to clips instead of having to keyframe it frame by frame.

[Ryan Elder]

Some of the shots, it's hidden if there is a lot of detail around, but the ones of clear blue sky, it's noticeable. I can see what they say as well.

I still might want a better quality lens for future projects though, one that is acceptably sharp while fully zoomed in. The Sigma 150-600 is a bit steep for me in price and not sure if I would need a lens that zooms all the way to 600mm. What about the Tamron 100-400. Is it sharp in it's full zoomed in form?

[Paul R Johnson]

Forgot to say the other day. In your clip the other day, the thing that I noticed was not the slight softness, which after all could be probably improved if you close the aperture a bit, or open it, as definition is related to the iris - but the wobble and jerks. The absolutely critical thing is pans and tilts. At long focal lengths you MUST resist the temptation to move if you have a poor pan and tilt head. People would rather see less creature and more smoothness. Going in close requires a very good camera support. Have you sorted this before collecting too much material?

[Brian Drysdale]

Originally Posted by Chris Hurd

Actually that's a Tamron or Sigma brand with an EF mount.

Canon doesn't make an EF 150-600.

This may be an old lens, I got this from the Panavision rental catalogue, so it may be well Panavised over the years.

I recall a Canon zoom lens with the same range that Optex in the UK used to modify when they they were in business. They converted the whole range of Canon telephoto lenses with the Universal mount system, so that you could switch to which ever camera mount you needed - there were a lot more mounts on film cameras in the past not just PL or PV.

[Paul R Johnson]

After dragging all my old cameras out, I thought I'd have a bit of a comparison with all the lenses. I've come to the conclusion that every one is well matched to the lens supplied with it, but less good on each others. The 750, for example has the same mount as the 200 and 100 series but the sense from the 750 is less sharp on the 100+200 series, which have lower maximum definition. Their lenses are softer on the 750. I repeated this with the older cameras in SD. The 5100 I have performs worse on the lens on the older 500, yet it's lens is less good then the 5100's. I've never noticed this before and assume that the kit lenses are designed to bring out the best in each one.

Ryan's post has caused me to spend some money and buy an adaptor for the JVC ⅓" mount so I can attach the B4 lenses I still have from older broadcast cameras to it. They'll be soft, of course, not being HD glass, but the magnification from the smaller sensor, plus the 2X adaptor should give me some very long lenses. The adaptor is purely a limo of alloy - so I'm going to lose definition due to the glass but also because of the small sensor. I wonder how bad it will be? A colleague with one says it is not good, BUT, he also refused to sell his adaptor to me as he uses it all the time - so it's worth a punt!

Your fault, Ryan - you owe me £125!

[Josh Bass]

Ah. Its all coming together now. Ryan is some sort of freelance marketing shill. Well done, various corporations.

[Chris Hurd]

Originally Posted by Brian Drysdale

This may be an old lens, I got this from the Panavision rental catalogue, so it may be well Panavised over the years.

Indeed, long ago there was a Canon 150-600 in FD mount:

https://global.canon/en/c-museum/product/nfd258.html

Looks like it's been a previous topic of discussion here on DVi:

https://www.dvinfo.net/forum/under-w...go-manual.html

[Ryan Elder]

Originally Posted by Paul R Johnson

Forgot to say the other day. In your clip the other day, the thing that I noticed was not the slight softness, which after all could be probably improved if you close the aperture a bit, or open it, as definition is related to the iris - but the wobble and jerks. The absolutely critical thing is pans and tilts. At long focal lengths you MUST resist the temptation to move if you have a poor pan and tilt head. People would rather see less creature and more smoothness. Going in close requires a very good camera support. Have you sorted this before collecting too much material?

Yeah I only moved the camera to adjust to the animals. However, I figured I would use the good parts of the video where it doesn't jerk so much. I have a fluid head pan and tilt tripod, and I've been able to move the lens successfully with planned actors so far, but when the animals are unpredictable, it's been hard to move with them in parts. But so far I've just been using the sections where it doesn't jerk so much.

As for the aperture, I've been keeping it more closed to get a deeper DOF, so the animals have more room to move around in focus, if that's okay. At 300mm you need quite a closed aperture, since the DOF is so shallow, if you don't, of course.