Jump to content

280/4 Apo Telyt R


dkCambridgeshire

Recommended Posts

Advertisement (gone after registration)

Is the aperture transferring arm on the extender functioning correctly.? You must mount the extender to the camera and then the lens to the extender. Once that is done you can dismount and mount lens+extender normally.

Link to post
Share on other sites

x
  • Replies 45
  • Created
  • Last Reply
Is the aperture transferring arm on the extender functioning correctly.? You must mount the extender to the camera and then the lens to the extender. Once that is done you can dismount and mount lens+extender normally.

 

Thanks for the reply.

 

For reference there are two levers inside the extender; one on left that looks like a little cube is moving more freely, i think that one stops down the lens during the exposure and the other on the right is stepped cam, that one also appears to be moving as i change F stop on the lens.

 

By aperture transferring arm you mean one on the right.

 

I have tried both mounting sequences and camera display shows same f3.4-f19 apperture stop range. What i mean by both sequnces is (a) mount Extender onto the camera first and (B) mount extender onto the lens first - it can be done by moving stop-down arm by finger.

 

Just to confirm R8 displays F stop correctly for lens only, and this is corroborated with other R lenses, plus results speak for themself no exposure errors.

 

Still baffled :(

Link to post
Share on other sites

Advertisement (gone after registration)

If you are using an R8 or R9, the aperture information when using the lens alone is transmitted by the ROM chip. If you are using the lens with a nonROM 1.4 extender the aperture information is trnsmitted by the mechanical linkage. So as I see it, there are still two possibilities (a) the mechanical R cam is faulty on the lens, or (B) the cam linkage is faulty on the extender.

 

What I would suggest is to see if you can try out the lens on an R camera previous to R8/9, that is, without ROM capability. If the display is correct, then the mechanical R cam on the lens is OK, and it must be the extender's linkage that's at fault. If it's not OK, then it's the lens's linkage that's at fault, but not showing up with an R8, because of the electronic transfer of information.

Link to post
Share on other sites

John,

 

Much appreciated on your help.

 

As I am not in position to check lens or lens/extender combination on pre R8/R9 body I will have to assume that extender linkage is faulty & return it.

 

Another thought; am i right in thinking that ROM chip only transmits type of lens into the camera (only useful with DMR & TTL flesh) and actual F stop is mechanically tranmitted by the stepped CAM - if so lens linkage is working correctly and extender is inducing fault.

 

Jaap,

 

Appreciate your input.

Link to post
Share on other sites

Jaap

 

No, if you have an R8/9 and a ROM lens, then I'm sure that the aperture setting is transmitted by the ROM chip, and the mechanical information is ognored. (For example, with the "new" 28-90 ROM zoom lens, the aperture varies with focal length setting, and the ROM chip sends the "true" aperture to the camera. Likewise with the 2X extender ROM, a ROM lens set to nominal f/22 will have f/45 sent to the camera by the extenders ROM processor.

 

It's also just possible that the camera mechanical linkage is not right, which shows up only with a non ROM lens. Have you tried non ROM lenses directly on the camera?

Link to post
Share on other sites

Jaap

 

No, if you have an R8/9 and a ROM lens, then I'm sure that the aperture setting is transmitted by the ROM chip, and the mechanical information is ognored. (For example, with the "new" 28-90 ROM zoom lens, the aperture varies with focal length setting, and the ROM chip sends the "true" aperture to the camera. Likewise with the 2X extender ROM, a ROM lens set to nominal f/22 will have f/45 sent to the camera by the extenders ROM processor.

 

It's also just possible that the camera mechanical linkage is not right, which shows up only with a non ROM lens. Have you tried non ROM lenses directly on the camera?

 

I tried other non ROM lenses and they work fine on their own - F stop on apperture ring corresponds to the camera display.

 

BTW Jaap is other guy who responded earlier, i should have included my signature :o

 

Ignore the aperture display in the viewfinder. My R8 shows the same apertures in the viewfinder that you're seeing when I use the 280/4 APO + 1.4x APO. The meter works fine, it's the aperture display in the viewfinder that looks odd.

 

Aha, now this is significant. So you are saying ignore display in viewfinder and shoot :)

 

Thank you all, I think I am very happy now.

 

Regards,

 

Mladen

Link to post
Share on other sites

I tried other non ROM lenses and they work fine on their own - F stop on apperture ring corresponds to the camera display.

 

BTW Jaap is other guy who responded earlier, i should have included my signature :o

 

 

Aha, now this is significant. So you are saying ignore display in viewfinder and shoot :)

 

Thank you all, I think I am very happy now.

 

Regards,

 

Mladen

 

Oops! Sorry Mladen, my mistake!

Link to post
Share on other sites

I see that I need to get home and see what my extender does on the VE 105-280. I never noticed anything amiss, but then I only use it on AE normally wide open and only watch the shutterspeed in the display, so it is perfectly possible I missed it.:o

Link to post
Share on other sites

Ignore the aperture display in the viewfinder. My R8 shows the same apertures in the viewfinder that you're seeing when I use the 280/4 APO + 1.4x APO. The meter works fine, it's the aperture display in the viewfinder that looks odd.

 

Thanks for the earlier post, as much as your answer is what i would like to hear, hence all the elation, an Engineer at the back of mind keeps enquiring how is this possible as we all know that f4 lens paired with 1.4 Extender becomes f5.6.

 

Just back from work so I repated mounting sequence;

Extender first, R8 metere display shows f3.4

Attach 280f4, R8 display shows f3.4 to f19 to correspond to lens f4-f22.

When I push (with plastic stick) leaver on the extender mounted onto the camera, R8 display will go up to f22, another mini mystery.

 

Only affirmative thought is that reagardless of what is on display camera meter must be metering light and setting shutter & aperture, display is just point of reference. So for in instance in shutter priority it can go as wide as f3.4 although in reality it is f5.6.

 

Enough ramblings from me, somebody please convince me.

 

Extender is S/N 3428***

 

Much appreciated,

 

Mladen

Link to post
Share on other sites

Not to hijack this thread but also about extenders - just 2X APO

 

Does anyone find any real-life problem using 280/4 + 2X APO on a Canon/Nikon FF body? I asked Doug before and under good light condition the combo is manageable on tripod. How manageable is it handhold (emergency only)?

 

It seems like 1~2 stop of the combo brings IQ up with APO quality; how does this compare to 1.4X combo wide open?

 

Just some final thoughts before I pull the trigger. I was in favor of 1.4X but the versatility of 2X to use on the 100/2.8 as well seems to out-weight the IQ of 1.4X + 280/4 alone.

Link to post
Share on other sites

A point for the DMR It focusses effortlessly with my 105-280 VE and 2x apoextender.

 

Hello jaapv: How do you compare the 105-280 with and without the 2X in term of focusing in full lightening, ok lightening or windy conditions?

 

Hello lct: I can feel the same thing and I can even image 560mm will be worse. However if taking a high IQ is more important (reason for extender) then I'll willing to invest it as a emergency backup. I'm with Doug that it will be a tripod lenses but sometimes if lightening is ok I'll willing to try handhold/beanbag type shooting.

Link to post
Share on other sites

This is doubtless in part a question of my own limitations, but I've found that the 280/4 + 2X Apo Extender really does need a sturdy tripod. I've even gone so far as to leave the legs unextended to maxiimise the rigidity. The other problem I find is that, with the extender, the "focus gearing" is increased (put loosely, the change of position of the plane of focus per degree of rotation of the focus ring) thus making focussing really quite critical.

Link to post
Share on other sites

Hello jaapv: How do you compare the 105-280 with and without the 2X in term of focusing in full lightening, ok lightening or windy conditions?

 

Hello lct: I can feel the same thing and I can even image 560mm will be worse. However if taking a high IQ is more important (reason for extender) then I'll willing to invest it as a emergency backup. I'm with Doug that it will be a tripod lenses but sometimes if lightening is ok I'll willing to try handhold/beanbag type shooting.

I fully appreciate the use of a tripod when possible, but usually it does not fit in with my style of shooting. I have been blessed with very stable hands, or will rely on a beanbag. As for focussing, I find it essential with long lenses to use the full matte screen, and then, with the clear R8/9 viewfinder, I find I can focus easily in almost all conditions. Obviously a single lens is a doddle, and bad light and a 2x extender more demanding, but it is quite possible. I do have the Brightscreen magnifier on the DMR since last year, and that is a great addition, extending my focussing ability right down into low light, but focussing was fine even before that.

Link to post
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...