Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Sony Alpha dSLR / Konica Minolta dSLR, Sony SLT

Reply
 
Thread Tools Search this Thread
Old Feb 17, 2006, 6:26 PM   #1
Junior Member
 
Join Date: Jan 2006
Posts: 6
Default

Can anyone please advise on a lens compatibility issue with my Dynax 5D,i have recently aquired a maxxum AF Zoom lens (70-210 F4.5/5.6) that i believe to be from a 35mm minolta camera,according to KM`s own website this lens along with many others is compatible with my camera (including the antishake feature),however when i first attached this lens i found thatit would not allow the camera shutter to fire?,i overcame this by changing the camera shutter priority to `release` in the custom menu.This did allow the shutter to fire but now the lens is unable to focus? I am unsure if the camera settings need to be changed further to allow this lens to lock focus,all i`m getting is this green focus inicator blinking,i am surprised by this as i believe this lens to be fully compatible.i have also found that looking through the view finder this lens when compaired to the 18-70 lens seems darker?,although this maybe a feature of the lens i`m not sure,any advise would be very helpfull.
steve06 is offline   Reply With Quote
Sponsored Links
Old Feb 17, 2006, 6:45 PM   #2
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Steve:

The lens should be fully compatible, without any special settings.

By changing the setting to shutter release, you're only telling the camera to fire even if it can't get focus lock.

You have to be careful using that setting, because if you don't half press the shutter button and wait for a lock before pressing it the rest of the way down, you can get out of focus images (because it will take the photo anyway).

Are you sure you're using it in enough light to focus? It sounds like not enough light (or not enough contrast in your subject) is probably the issue. That's not really a lens that's designed to work well in low light (and indoors is low light to a camera).

If you zoom in much, it's not going to be very bright (largest available aperture is down to f/5.6 on the long end).

The maximum available aperture will also impact brightness of the viewfinder (so you can have problems seeing in low light, just like the camera's AF can have problems focusing in low light if the lens isn't bright enough).

The kit lens is brighter on it's wide end (f/3.5), but it's also down to f/5.6 by the time you zoom into around 35mm with it. So, it's not the brightest lens in less than optimum lighting either.

I'd make sure the contacts are clean on it first (wipe 'em off with an old t-shirt if nothing else), and make sure it's seated well when you mount it.

Then, see how it behaves in better light. Chances are, you're just zooming in so much that the camera isn't getting enough light to focus (and f/4.5 isn't the brightest around on the wide end of a lens either, much less dropping off to f/5.6 as you zoom in more towards the long end).

If you have any type of filter on it, I'd remove it, too. A cheap filter can cause reflections and degrade optical quality, and some filters can significantly reduce the amount of light getting through to the lens (for example, a polarizer).

If it doesn't work after cleaning the contacts and trying it in better light outdoors, then it could be defective.


JimC is offline   Reply With Quote
Old Feb 17, 2006, 7:33 PM   #3
Junior Member
 
Join Date: Jan 2006
Posts: 6
Default

Thanks Jim for your advise, i have been testing the lens in rather poor light i`ll try it again in better conditions although i`m not sure that returning the camera to the settings it was using on the standard lens will allow the shutter to fire?,maybe as you suggest i`m getting a bad contact between camera and lens,as you say the lens should be compatible,i did check this prior to buying it on KM`s support site ,i`ll take your advise onboard and experiment further,thanks again.
steve06 is offline   Reply With Quote
Old Feb 17, 2006, 7:46 PM   #4
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

If it's not getting focus lock (steady versus blinking green light), it's not supposed to take a photo. That's to prevent you from taking out of focus shots. ;-)

So, by changing the setting in the camera, you're just overriding the default safeguard.

Does it try to focus (focus mechanism hunts before the light blinks)?

If so, chances are, it's just that light is too low (and/or not enough contrast in your subject) for the camera to see well enough to focus.

Even outdoors in less than optimum lighting, autofocus can be "iffy" with a long zoom that drops off to f/5.6 on it's long end, and indoor lighting is much lower.

To put things into perspective, the aperture scale in one stop increments goes f/1.0 (theortically larger apertures are availalbe, too), f/1.4, f/2.0, f/2.8, f/4.0, f/5.6, f/8, f/11, f/16, f/22, etc.

With each one stop move to a smaller aperture (represented by larger f/stop numbers), you will need shutter speeds twice as long for proper exposure, given the same lighting and ISO speed.

That also means that with each one stop move to a smaller aperture (higher f/stop number), you lose half the light getting through the lens to the AF sensors and viewfinder (and to the main CCD when the mirror flips and shutter opens).

A brighter (a.k.a., faster) lens helps a camera to "see" better for Autofocus Purposes. You often seen complaints of the Autofocus hunting when camera owners buy inexpensive long zoom lenses (with maximum available apertures of f/5.6 or f/6.3 on their long end) and use them in less than optimum lighting.

Any lens is a compromse. A lens that isn't as bright is going to be smaller and lighter (and less expensive) compared to a brighter lens with the same focal range. But, it's going to be less than desirable for use in some conditions. You make tradeoffs. Staying towards the wide end of the zoom range may help a little in less than optimum lighting, too.

Try it in better light and see what happens after making sure the contacts are making a good connection (clean 'em and remount the lens). If it doesn't work in good light either, then it might be defective.

JimC is offline   Reply With Quote
Old Feb 17, 2006, 8:28 PM   #5
Senior Member
 
tmoreau's Avatar
 
Join Date: Dec 2005
Posts: 477
Default

I have that lens, but its on its way to ebay! Its very dim, I could hardly get it to focus indoors with my 5D unless I turned on every light in the house and aimed it at a bright spot. If the camera cant focus you get the blinking dot in the viewfinder and the shutter wont open. Release priority is you telling the camera that out of focus shots are ok, you dont want that. You have to use this lens when there is a LOT of light, like daytime outdoors. This lens is fully compatible with your camera and sounds like its working fine.
tmoreau is offline   Reply With Quote
Old Feb 17, 2006, 8:38 PM   #6
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

A lens like that probably isn't the sharpest tool in the drawer, either.

So, with smaller available apertures (meaning less light gets through the lens for AF purposes), combined with some softness at wide open apertures (and a camera will always focus with the lens set to wide open apertures), you can get a lens that's not really suited for use in less than optimum lighting. A number of zoom lenses will fall into this category.

In good light outdoors (so that the camera's AF sensors can see better to focus) with the aperture stopped down a bit when shooting to increase the sharpness of the images, it will probably work OK.

Again, any lens is a compromise (size, weight, build quality, optical quality, brightness focal range, etc.). Try it in better light and see what happens.

JimC is offline   Reply With Quote
Old Feb 18, 2006, 2:24 PM   #7
Junior Member
 
Join Date: Jan 2006
Posts: 6
Default

I have experimented again with this lens all attempts were done outdoors in the best light i could manage,some shots were even taken with some direct sunlight in view,however the shutter still won`t release,all i seem to get is the autofocus searching for light and failing to focus.i am yet to fire a single shot with this lens,i have considered changing it for another minolta AF lens or even a different manufacturers altogether.I originally kept with a minolta lens to try to ensure good compatibility with my 5D,but am now considering a third party DSLR only model.i am basically looking for 3 lenses to go with my kit lens,a wide,macro,and telephoto having downloaded KM`s lens compatibility chart i believed it best to use only minolta lenses,now i`m not so sure,tamron,sigma and tokina all produce good alternatives.
steve06 is offline   Reply With Quote
Old Feb 18, 2006, 4:47 PM   #8
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

Make sure you have the MF/AF switch in the AF position, too; and you may want to see what focus mode you're using. See if using the center focus point isn't better.

If it won't work in good light outdoors, the lens you bought is likely defective (it should be 100% compatible).

But, even one in excellent condition isn't exactly one to write home about. That lens sells for around $60 to $70 in excellent condition from vendors like KEH.COM. It's not a great quality lens. ;-)

Look around for a Minolta 70-210mm f/4 (not the other 70-210mm versions) for a lens that's much higher quality yet won't break the bank. If you're a careful shopper, you should be able to find one for between $100 and $200. They were less a few months back.

For indoor use with moving subjects without a flash, you'll want a 70-210mm f/2.8 (twice as bright as f/4 but it will cost you more and is larger and heavier).


JimC is offline   Reply With Quote
Old Feb 18, 2006, 5:31 PM   #9
Junior Member
 
Join Date: Jan 2006
Posts: 6
Default

Thanks for that Jim,would i be right in saying that a minolta 70-210 F4 would be able to pull in more light than my current lensand therefor be able to lock focus better (i`m not sure if this lens is classed as fixed focus),also would this lens be any lighterthrough the viewfinder,i have also been considering a Sigma 28-200mm f3.5 - 5.6?
steve06 is offline   Reply With Quote
Old Feb 18, 2006, 6:00 PM   #10
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

If you're zooming in much, f/4 is exactly twice as bright as f/5.6 (the largest available aperture at the long end on the other zooms you're looking at). That gets more light to the viewfinder (and to the AF sensors for focusing purposes).

It's a much sharper lens at wide open apertures compared to the cheaper 70-200mm zooms you'll find, too (which will also help the camera to focus easier).

But, it's not going to be a speed demon, and shutter speeds may be too slow for non-stationary subjects in many indoor conditions if you don't want to use a flash.

If you're trying to use a camera indoors without a flash, get yourself lenses that can maintain f/2.8 throughout their focal range in zooms (but primes are better for this purpose since you can find them sharper and brighter for less money compared to zooms).

One example of a bright zoom is the Minolta 28-75mm f/2.8 (about $400 new)

or, on the longer end, something like a Sigma 70-200mm f/2.8 EX APO (about $800 new). That's 4 times as bright as the lens you just bought on the long end (f/2.8 is four times as bright as f/5.6).

Again, any lens is a compromise. A brighter lens will be larger, heavier and more expensive.

If you don't need that kind of focal range indoors, you can get buy with a less expensive lens for use in better light outdoors.

For indoor use without a flash, more often than not, I've got a Minolta 28mm f/2 on my 5D. That's twice as bright as an f/2.8 zoom, 4 times as bright as an f/4 zoom, and 8 times as bright as a zoom with a maximum aperture of f/5.6.

Most of my indoor photos are taken on the wide end, and a 28mm is a good fit for my shooting. But, what I need or use is not necessarily what someone else needs or uses.

I've also got a 50mm f/1.7 for when I need something a bit longer; as well as a 100mm f/2 and 135mm f/2.8

In a pinch, I've got a Tamron 20-40mm f'/2.7-3.5 and 35-105mm f/2.8 zooms that I can use, too. But, the 35-105mm f/2.8 is a tad soft wide open (much better down a stop or so), for my tastes.

I really don't have a need for anyting longer than what I've got for indoor use. But, if I was shooting night sports or something, I'd get a decent zoom with f/2.8 throughout the focal range that's longer than what I've got now.

You'd do better with the Minolta 28-75mm f/2.8 by most accounts compared to the Tamrons I've got in standard focal ranges.

The Sigma 70-200mm f/2.8 EX (DG or non DG) is well liked by most users for something longer indoors.

At around $800.00 new, this Sigma is far less expensive compared to something like a Minolta 70-200mm f/2.8G SSM (it's around $1,800.00)

What are you planning to shoot. Do you really need to use a lens that long indoors? Can you use a flash?

A good compromise would be the Minolta 70-210mm f/4 that I mentioned.

It's not really bright enough for indoor use without a flash of non-stationary subjects in most lighting. But, it's going to be a much higher quality zoom lens compared to anything else you'll find in it's focal range and price range from the user reports and images I've seen.


JimC is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 5:31 AM.